远程主机上安装的 squid 版本低于 4.11-1。因此，它受到 ALAS2SQUID4-2023-008 公告中提及的多个漏洞影响。

  - 在 Squid 4.7 及之前的版本中发现问题。处理标记 esi 时：如果已启用 ESI，则 Squid 会调用 ESIExpression: : Evaluate。在对表达式求值时，此函数使用固定堆栈缓冲区保留该表达式。在处理表达式时，它可以对栈顶求值，也可以向堆栈中添加新成员。在添加新成员时，未进行检查以确保堆栈不会溢出。(CVE-2019-12519)

  - 在 Squid 4.7 及之前的版本中发现问题。当 Squid 解析 ESI 时，它会将 ESI 元素保留在 ESIContext 中。ESIContext 包含一个用于保存 ESIElement 堆栈的缓冲区。在解析新的 ESIElement 时，可以通过 addStackElement 添加该元素。addStackElement 对此缓冲区中的元素数量进行了检查，但结果为差 1，进而导致 1 个元素堆溢出。溢出位于同一结构内，因此不会影响邻近的内存块，只会在处理时导致崩溃。
    (CVE-2019-12521)

  - 在 Squid 3.3.9 至 3.5.28 及 4.x 至 4.7 版本中发现问题。当 Squid 配置为使用摘要式认证时，它会解析标头 Proxy-Authorization。它会搜寻特定标记，例如域、uri 和 qop。Squid 会检查此标记的值开头是否为引号，且结尾是否为 1。如果是，则它会对其长度减 2 执行 memcpy。Squid 始终不检查该值是否仅为单引号（将满足其要求），从而导致对其长度减 1 执行 memcpy。(CVE-2019-12525)

  - 在 Squid 5.0.2 之前的版本中发现问题。远程攻击者可重播嗅探到的摘要式身份验证 nonce，以访问本来被禁止的资源。发生此问题的原因在于攻击者可使 nonce 引用计数器（短整数）溢出。如果系统释放了池化的令牌凭据（而不是作为有效凭据重播），则可能会发生远程代码执行。(CVE-2020-11945)

请注意，Nessus 尚未测试这些问题，而是只依据应用程序自我报告的版本号进行判断。

远程 Oracle Linux 8 主机上安装的程序包受到 ELSA-2020-4743 公告中提及的多个漏洞的影响。

  - 在 Squid 4.10 之前的版本中发现问题。它允许构建的 FTP 服务器触发堆内存中敏感信息（例如，与其他用户的会话或非 Squid 进程相关的信息）的泄露。(CVE-2019-12528)

  - 在 Squid 4.10 之前的版本中发现问题。由于不正确的缓冲区管理，导致远程客户端可在充当反向代理的 Squid 实例中造成缓冲区溢出。(CVE-2020-8450)

  - 在 Squid（版本低于 4.12 以及为低于 5.0.3 的 5.x）的 http/ContentLengthInterpreter.cc 中发现问题。可成功针对 HTTP 缓存发动请求走私和中毒攻击。客户端发送带有 Content-Length 标头的 HTTP 请求，该标头包含长度字段值的 +\- 或不常见 shell 空白字符前缀。(CVE-2020-15049)

  - 可信对等机可利用 Squid（版本为 4.13 以及 5.0.4 之前的 5.x），通过在处理构建的 Cache Digest 响应消息期间消耗所有可用的 CPU 周期，执行拒绝服务。仅当 cache_peer 与缓存摘要功能一起使用时才会发生此问题。存在该问题的原因是 peer_digest.cc 中的 peerDigestHandleReply() 活锁未正确处理 EOF。(CVE-2020-24606)

  - 在 Squid 4.10 之前的版本中发现问题。此问题可以非预期的方式解释构建的 HTTP 请求，以访问早期安全过滤器禁止的服务器资源，这是输入验证不正确所致。
    (CVE-2020-8449)

  - 在 Squid 4.7 及之前的版本中发现问题。- 当 Squid 解析 ESI 时，它会将 ESI 元素保留在 ESIContext 中。ESIContext 包含一个用于保存 ESIElement 堆栈的缓冲区。在解析新的 ESIElement 时，可以通过 addStackElement 添加该元素。addStackElement 对此缓冲区中的元素数量进行了检查，但结果为差 1，进而导致 1 个元素堆溢出。溢出位于同一结构内，因此不会影响邻近的内存块，只会在处理时导致崩溃。
    (CVE-2019-12521)

  - 在 Squid 4.9 之前的版本中发现问题。处理 URN 请求时，会发出相应的 HTTP 请求。此 HTTP 请求未经过传入 HTTP 请求经过的访问权限检查，这会造成所有访问检查被绕过，并且允许访问受限制的 HTTP 服务器，例如，攻击者可连接到仅监听本地主机的 HTTP 服务器。(CVE-2019-12523)

  - 在 Squid 4.7 及之前的版本中发现问题。- 处理来自用户的请求时，Squid 会检查其规则以查看是否应拒绝该请求。默认情况下，Squid 带有阻止访问缓存管理器的规则，该管理器可为维护者提供详细的服务器信息。此规则通过 url_regex 实现。url_regex 的规则 URL 处理程序可解码传入的请求，这使攻击者可以对自己的 URL 进行编码以绕过 url_regex 检查，并获得对被阻止资源的访问权限。(CVE-2019-12524)

  - 在 Squid 4.9 之前的版本中发现问题。Squid 中的 URN 响应处理受到基于堆的缓冲区溢出漏洞影响。从远程服务器接收数据以响应 URN 请求时，Squid 无法确保响应内容都在缓冲区内。攻击者可利用此漏洞造成堆中的控制数据溢出。(CVE-2019-12526)

  - 在 Squid 2.x 至 2.7.STABLE9、3.x 至 3.5.28 和 4.x 至 4.7 版本中发现了一个问题。当 Squid 配置为使用基本身份验证时，它会通过 uudecode 解析标头 Proxy-Authorization。
    uudecode 会通过迭代输入并检查其表格来确定需要解码的字节数。然后，此长度会被用于开始解码该字符串。但没有任何检查可以确保其计算出的长度不超过输入缓冲区的长度。这会导致邻近内存也被解码。除非 Squid 维护人员已配置在错误页面显示用户名，否则攻击者将无法检索已解码的数据。(CVE-2019-12529)

  - 使用特定 Web 浏览器时，Squid 4.9 的之前版本未正确处理 cachemgr.cgi 的主机（又称为主机名）参数中的 HTML。(CVE-2019-18860)

  - 在版本低于 4.12 以及版本为低于 5.0.3 的 5.x 的 Squid 中发现问题。由于使用了潜在危险的函数，当打开与攻击者控制的 HTTPS 服务器的 TLS 连接时，Squid 和默认证书验证帮助程序容易受到拒绝服务的攻击。之所以发生此问题，是因为无法识别的错误值被映射到了 NULL；但按照预期，后来输入的代码可将每个错误值都映射到有效的错误字符串。(CVE-2020-14058)

  - 在 Squid 4.7 及其之前的所有版本和第 5 版中发现一个问题。当接收请求时，Squid 会检查其缓存以查看其是否可提供响应，它通过对请求的绝对 URL 进行 MD5 哈希来实现此操作。
    如果找到，则为请求提供服务。绝对 URL 可包含针对某些协议解码后的 UserInfo（用户名和密码），此解码后的信息会附加到网域之前。攻击者可借此提供具有特殊字符的用户名来分隔域，并将 URL 的其余部分视为路径或查询字符串。攻击者可首先使用编码的用户名向其域发出请求，然后当收到解码为确切 URL 的目标域请求时，程序会提供攻击者的 HTML，而不是真正的 HTML。在同时充当反向代理的 Squid 服务器上，这允许攻击者访问只有反向代理才能使用的功能，例如 ESI。(CVE-2019-12520)

  - 由于未正确终止字符串，Squid cachemgr.cgi 4.0 到 4.7 版本可能会访问未分配的内存。在具有内存访问保护的系统上，这可能造成 CGI 进程意外终止，进而导致所有使用它的客户端发生拒绝服务。(CVE-2019-12854)

  - 在 Squid 3.x 和 4.x 至 4.8 版本中发现问题。由于输入验证不正确，存在基于堆的缓冲区溢出，可导致使用代理的所有客户端遭受拒绝服务攻击。由于此漏洞在正常安全检查之前发生，因此严重性较高；任何可以访问代理端口的远程客户端都可以通过构建的 URI 方案轻松执行攻击。(CVE-2019-18676)

  - 当使用 append_domain 设置时，在 Squid 3.x 和 4.x 到 4.8 版本中发现一个问题（因为附加字符不能与主机名长度限制正确地进行交互）。由于消息处理不正确，可能会将流量错误地重定向到流量不应流向的源。
    (CVE-2019-18677)

  - 在 Squid 3.x 和 4.x 至 4.8 版本中发现问题。攻击者可利用此问题，通过前端软件将 HTTP 请求传递至 Squid 实例，此实例以不同的方式拆分 HTTP 请求管道。生成的响应消息通过任意 URL 的攻击者控制内容破坏缓存（客户端与 Squid 之间）。攻击者客户端和 Squid 之间的软件会受到影响。但 Squid 本身不会受到影响，所有上游服务器也不会受到影响。此问题与请求标头有关，其中包含标头名称与冒号之间的空格。(CVE-2019-18678)

  - 在 Squid 2.x、3.x 及 4.x 至 4.8 版本中发现问题。由于不正确的数据管理，导致在处理 HTTP 摘要式身份验证时容易发生信息泄露。Nonce 令牌包含位于堆内存分配中的指针的原始字节值。此信息会减少 ASLR 保护，并且可能会协助攻击者将内存区域隔离至目标，从而实现远程代码执行攻击。
    (CVE-2019-18679)

请注意，Nessus 尚未测试这些问题，而是只依据应用程序自我报告的版本号进行判断。

The remote Rocky Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2020:4743 advisory.

  - An issue was discovered in Squid through 4.7 and 5. When receiving a request, Squid checks its cache to     see if it can serve up a response. It does this by making a MD5 hash of the absolute URL of the request.
    If found, it servers the request. The absolute URL can include the decoded UserInfo (username and     password) for certain protocols. This decoded info is prepended to the domain. This allows an attacker to     provide a username that has special characters to delimit the domain, and treat the rest of the URL as a     path or query string. An attacker could first make a request to their domain using an encoded username,     then when a request for the target domain comes in that decodes to the exact URL, it will serve the     attacker's HTML instead of the real HTML. On Squid servers that also act as reverse proxies, this allows     an attacker to gain access to features that only reverse proxies can use, such as ESI. (CVE-2019-12520)

  - An issue was discovered in Squid through 4.7. When Squid is parsing ESI, it keeps the ESI elements in     ESIContext. ESIContext contains a buffer for holding a stack of ESIElements. When a new ESIElement is     parsed, it is added via addStackElement. addStackElement has a check for the number of elements in this     buffer, but it's off by 1, leading to a Heap Overflow of 1 element. The overflow is within the same     structure so it can't affect adjacent memory blocks, and thus just leads to a crash while processing.
    (CVE-2019-12521)

  - An issue was discovered in Squid before 4.9. When handling a URN request, a corresponding HTTP request is     made. This HTTP request doesn't go through the access checks that incoming HTTP requests go through. This     causes all access checks to be bypassed and allows access to restricted HTTP servers, e.g., an attacker     can connect to HTTP servers that only listen on localhost. (CVE-2019-12523)

  - An issue was discovered in Squid through 4.7. When handling requests from users, Squid checks its rules to     see if the request should be denied. Squid by default comes with rules to block access to the Cache     Manager, which serves detailed server information meant for the maintainer. This rule is implemented via     url_regex. The handler for url_regex rules URL decodes an incoming request. This allows an attacker to     encode their URL to bypass the url_regex check, and gain access to the blocked resource. (CVE-2019-12524)

  - An issue was discovered in Squid before 4.9. URN response handling in Squid suffers from a heap-based     buffer overflow. When receiving data from a remote server in response to an URN request, Squid fails to     ensure that the response can fit within the buffer. This leads to attacker controlled data overflowing in     the heap. (CVE-2019-12526)

  - An issue was discovered in Squid before 4.10. It allows a crafted FTP server to trigger disclosure of     sensitive information from heap memory, such as information associated with other users' sessions or non-     Squid processes. (CVE-2019-12528)

  - An issue was discovered in Squid 2.x through 2.7.STABLE9, 3.x through 3.5.28, and 4.x through 4.7. When     Squid is configured to use Basic Authentication, the Proxy-Authorization header is parsed via uudecode.
    uudecode determines how many bytes will be decoded by iterating over the input and checking its table. The     length is then used to start decoding the string. There are no checks to ensure that the length it     calculates isn't greater than the input buffer. This leads to adjacent memory being decoded as well. An     attacker would not be able to retrieve the decoded data unless the Squid maintainer had configured the     display of usernames on error pages. (CVE-2019-12529)

  - Due to incorrect string termination, Squid cachemgr.cgi 4.0 through 4.7 may access unallocated memory. On     systems with memory access protections, this can cause the CGI process to terminate unexpectedly,     resulting in a denial of service for all clients using it. (CVE-2019-12854)

  - An issue was discovered in Squid 3.x and 4.x through 4.8. Due to incorrect input validation, there is a     heap-based buffer overflow that can result in Denial of Service to all clients using the proxy. Severity     is high due to this vulnerability occurring before normal security checks; any remote client that can     reach the proxy port can trivially perform the attack via a crafted URI scheme. (CVE-2019-18676)

  - An issue was discovered in Squid 3.x and 4.x through 4.8 when the append_domain setting is used (because     the appended characters do not properly interact with hostname length restrictions). Due to incorrect     message processing, it can inappropriately redirect traffic to origins it should not be delivered to.
    (CVE-2019-18677)

  - An issue was discovered in Squid 3.x and 4.x through 4.8. It allows attackers to smuggle HTTP requests     through frontend software to a Squid instance that splits the HTTP Request pipeline differently. The     resulting Response messages corrupt caches (between a client and Squid) with attacker-controlled content     at arbitrary URLs. Effects are isolated to software between the attacker client and Squid. There are no     effects on Squid itself, nor on any upstream servers. The issue is related to a request header containing     whitespace between a header name and a colon. (CVE-2019-18678)

  - An issue was discovered in Squid 2.x, 3.x, and 4.x through 4.8. Due to incorrect data management, it is     vulnerable to information disclosure when processing HTTP Digest Authentication. Nonce tokens contain the     raw byte value of a pointer that sits within heap memory allocation. This information reduces ASLR     protections and may aid attackers isolating memory areas to target for remote code execution attacks.
    (CVE-2019-18679)

  - Squid before 4.9, when certain web browsers are used, mishandles HTML in the host (aka hostname) parameter     to cachemgr.cgi. (CVE-2019-18860)

  - An issue was discovered in Squid before 4.12 and 5.x before 5.0.3. Due to use of a potentially dangerous     function, Squid and the default certificate validation helper are vulnerable to a Denial of Service when     opening a TLS connection to an attacker-controlled server for HTTPS. This occurs because unrecognized     error values are mapped to NULL, but later code expects that each error value is mapped to a valid error     string. (CVE-2020-14058)

  - An issue was discovered in http/ContentLengthInterpreter.cc in Squid before 4.12 and 5.x before 5.0.3. A     Request Smuggling and Poisoning attack can succeed against the HTTP cache. The client sends an HTTP     request with a Content-Length header containing +\ - or an uncommon shell whitespace character prefix     to the length field-value. (CVE-2020-15049)

  - Squid before 4.13 and 5.x before 5.0.4 allows a trusted peer to perform Denial of Service by consuming all     available CPU cycles during handling of a crafted Cache Digest response message. This only occurs when     cache_peer is used with the cache digests feature. The problem exists because peerDigestHandleReply()     livelocking in peer_digest.cc mishandles EOF. (CVE-2020-24606)

  - An issue was discovered in Squid before 4.10. Due to incorrect input validation, it can interpret crafted     HTTP requests in unexpected ways to access server resources prohibited by earlier security filters.
    (CVE-2020-8449)

  - An issue was discovered in Squid before 4.10. Due to incorrect buffer management, a remote client can     cause a buffer overflow in a Squid instance acting as a reverse proxy. (CVE-2020-8450)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Multiple security issues were discovered in the Squid proxy caching server, which could result in the bypass of security filters, information disclosure, the execution of arbitrary code or denial of service.

The remote Redhat Enterprise Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2020:4743 advisory.

    Squid is a high-performance proxy caching server for web clients, supporting FTP, Gopher, and HTTP data     objects.

    The following packages have been upgraded to a later upstream version: squid (4.11). (BZ#1829467)

    Security Fix(es):

    * squid: Improper input validation in request allows for proxy manipulation (CVE-2019-12520)

    * squid: Off-by-one error in addStackElement allows for heap buffer overflow and crash (CVE-2019-12521)

    * squid: Improper input validation in URI processor (CVE-2019-12523)

    * squid: Improper access restriction in url_regex may lead to security bypass (CVE-2019-12524)

    * squid: Heap overflow issue in URN processing (CVE-2019-12526)

    * squid: Information Disclosure issue in FTP Gateway (CVE-2019-12528)

    * squid: Out of bounds read in Proxy-Authorization header causes DoS (CVE-2019-12529)

    * squid: Denial of service in cachemgr.cgi (CVE-2019-12854)

    * squid: Buffer overflow in URI processor (CVE-2019-18676)

    * squid: Cross-Site Request Forgery issue in HTTP Request processing (CVE-2019-18677)

    * squid: HTTP Request Splitting issue in HTTP message processing (CVE-2019-18678)

    * squid: Information Disclosure issue in HTTP Digest Authentication (CVE-2019-18679)

    * squid: Mishandled HTML in the host parameter to cachemgr.cgi results in insecure behaviour     (CVE-2019-18860)

    * squid: Improper input validation issues in HTTP Request processing (CVE-2020-8449)

    * squid: Buffer overflow in reverse-proxy configurations (CVE-2020-8450)

    * squid: DoS in TLS handshake (CVE-2020-14058)

    * squid: Request smuggling and poisoning attack against the HTTP cache (CVE-2020-15049)

    * squid: Improper input validation could result in a DoS (CVE-2020-24606)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

    Additional Changes:

    For detailed information on changes in this release, see the Red Hat Enterprise Linux 8.3 Release Notes     linked from the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - An issue was discovered in Squid through 4.7. When Squid is parsing ESI, it keeps the ESI elements in     ESIContext. ESIContext contains a buffer for holding a stack of ESIElements. When a new ESIElement is     parsed, it is added via addStackElement. addStackElement has a check for the number of elements in this     buffer, but it's off by 1, leading to a Heap Overflow of 1 element. The overflow is within the same     structure so it can't affect adjacent memory blocks, and thus just leads to a crash while processing.
    (CVE-2019-12521)

Note that Nessus relies on the presence of the package as reported by the vendor.

The remote Alibaba Cloud Linux 3 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALINUX3-SA-2022:0124 advisory.

    Package updates are available for Alibaba Cloud Linux 3 that fix the following vulnerabilities:

    CVE-2019-12519:
    An issue was discovered in Squid through 4.7. When handling the tag esi:when when ESI is enabled, Squid     calls ESIExpression::Evaluate. This function uses a fixed stack buffer to hold the expression while it's     being evaluated. When processing the expression, it could either evaluate the top of the stack, or add a     new member to the stack. When adding a new member, there is no check to ensure that the stack won't     overflow.

    CVE-2019-12520:
    An issue was discovered in Squid through 4.7 and 5. When receiving a request, Squid checks its cache to     see if it can serve up a response. It does this by making a MD5 hash of the absolute URL of the request.
    If found, it servers the request. The absolute URL can include the decoded UserInfo (username and     password) for certain protocols. This decoded info is prepended to the domain. This allows an attacker to     provide a username that has special characters to delimit the domain, and treat the rest of the URL as a     path or query string. An attacker could first make a request to their domain using an encoded username,     then when a request for the target domain comes in that decodes to the exact URL, it will serve the     attacker's HTML instead of the real HTML. On Squid servers that also act as reverse proxies, this allows     an attacker to gain access to features that only reverse proxies can use, such as ESI.

    CVE-2019-12521:
    An issue was discovered in Squid through 4.7. When Squid is parsing ESI, it keeps the ESI elements in     ESIContext. ESIContext contains a buffer for holding a stack of ESIElements. When a new ESIElement is     parsed, it is added via addStackElement. addStackElement has a check for the number of elements in this     buffer, but it's off by 1, leading to a Heap Overflow of 1 element. The overflow is within the same     structure so it can't affect adjacent memory blocks, and thus just leads to a crash while processing.

    CVE-2019-12523:
    An issue was discovered in Squid before 4.9. When handling a URN request, a corresponding HTTP request is     made. This HTTP request doesn't go through the access checks that incoming HTTP requests go through. This     causes all access checks to be bypassed and allows access to restricted HTTP servers, e.g., an attacker     can connect to HTTP servers that only listen on localhost.

    CVE-2019-12524:
    An issue was discovered in Squid through 4.7. When handling requests from users, Squid checks its rules to     see if the request should be denied. Squid by default comes with rules to block access to the Cache     Manager, which serves detailed server information meant for the maintainer. This rule is implemented via     url_regex. The handler for url_regex rules URL decodes an incoming request. This allows an attacker to     encode their URL to bypass the url_regex check, and gain access to the blocked resource.

    CVE-2019-12525:
    An issue was discovered in Squid 3.3.9 through 3.5.28 and 4.x through 4.7. When Squid is configured to use     Digest authentication, it parses the header Proxy-Authorization. It searches for certain tokens such as     domain, uri, and qop. Squid checks if this token's value starts with a quote and ends with one. If so, it     performs a memcpy of its length minus 2. Squid never checks whether the value is just a single quote     (which would satisfy its requirements), leading to a memcpy of its length minus 1.

    CVE-2019-12526:
    An issue was discovered in Squid before 4.9. URN response handling in Squid suffers from a heap-based     buffer overflow. When receiving data from a remote server in response to an URN request, Squid fails to     ensure that the response can fit within the buffer. This leads to attacker controlled data overflowing in     the heap.

    CVE-2019-12527:
    An issue was discovered in Squid 4.0.23 through 4.7. When checking Basic Authentication with     HttpHeader::getAuth, Squid uses a global buffer to store the decoded data. Squid does not check that the     decoded length isn't greater than the buffer, leading to a heap-based buffer overflow with user controlled     data.

    CVE-2019-12528:
    An issue was discovered in Squid before 4.10. It allows a crafted FTP server to trigger disclosure of     sensitive information from heap memory, such as information associated with other users' sessions or non-     Squid processes.

    CVE-2019-12529:
    An issue was discovered in Squid 2.x through 2.7.STABLE9, 3.x through 3.5.28, and 4.x through 4.7. When     Squid is configured to use Basic Authentication, the Proxy-Authorization header is parsed via uudecode.
    uudecode determines how many bytes will be decoded by iterating over the input and checking its table. The     length is then used to start decoding the string. There are no checks to ensure that the length it     calculates isn't greater than the input buffer. This leads to adjacent memory being decoded as well. An     attacker would not be able to retrieve the decoded data unless the Squid maintainer had configured the     display of usernames on error pages.

    CVE-2019-12854:
    Due to incorrect string termination, Squid cachemgr.cgi 4.0 through 4.7 may access unallocated memory. On     systems with memory access protections, this can cause the CGI process to terminate unexpectedly,     resulting in a denial of service for all clients using it.

    CVE-2019-13345:
    The cachemgr.cgi web module of Squid through 4.7 has XSS via the user_name or auth parameter.

    CVE-2019-18676:
    An issue was discovered in Squid 3.x and 4.x through 4.8. Due to incorrect input validation, there is a     heap-based buffer overflow that can result in Denial of Service to all clients using the proxy. Severity     is high due to this vulnerability occurring before normal security checks; any remote client that can     reach the proxy port can trivially perform the attack via a crafted URI scheme.

    CVE-2019-18677:
    An issue was discovered in Squid 3.x and 4.x through 4.8 when the append_domain setting is used (because     the appended characters do not properly interact with hostname length restrictions). Due to incorrect     message processing, it can inappropriately redirect traffic to origins it should not be delivered to.

    CVE-2019-18678:
    An issue was discovered in Squid 3.x and 4.x through 4.8. It allows attackers to smuggle HTTP requests     through frontend software to a Squid instance that splits the HTTP Request pipeline differently. The     resulting Response messages corrupt caches (between a client and Squid) with attacker-controlled content     at arbitrary URLs. Effects are isolated to software between the attacker client and Squid. There are no     effects on Squid itself, nor on any upstream servers. The issue is related to a request header containing     whitespace between a header name and a colon.

    CVE-2019-18679:
    An issue was discovered in Squid 2.x, 3.x, and 4.x through 4.8. Due to incorrect data management, it is     vulnerable to information disclosure when processing HTTP Digest Authentication. Nonce tokens contain the     raw byte value of a pointer that sits within heap memory allocation. This information reduces ASLR     protections and may aid attackers isolating memory areas to target for remote code execution attacks.

    CVE-2019-18860:
    Squid before 4.9, when certain web browsers are used, mishandles HTML in the host (aka hostname) parameter     to cachemgr.cgi.

    CVE-2020-11945:
    An issue was discovered in Squid before 5.0.2. A remote attacker can replay a sniffed Digest     Authentication nonce to gain access to resources that are otherwise forbidden. This occurs because the     attacker can overflow the nonce reference counter (a short integer). Remote code execution may occur if     the pooled token credentials are freed (instead of replayed as valid credentials).

    CVE-2020-14058:
    An issue was discovered in Squid before 4.12 and 5.x before 5.0.3. Due to use of a potentially dangerous     function, Squid and the default certificate validation helper are vulnerable to a Denial of Service when     opening a TLS connection to an attacker-controlled server for HTTPS. This occurs because unrecognized     error values are mapped to NULL, but later code expects that each error value is mapped to a valid error     string.

    CVE-2020-15049:
    An issue was discovered in http/ContentLengthInterpreter.cc in Squid before 4.12 and 5.x before 5.0.3. A     Request Smuggling and Poisoning attack can succeed against the HTTP cache. The client sends an HTTP     request with a Content-Length header containing +\ - or an uncommon shell whitespace character prefix     to the length field-value.

    CVE-2020-15810:
    An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP     Request Smuggling attacks may succeed against HTTP and HTTPS traffic. This leads to cache poisoning. This     allows any client, including browser scripts, to bypass local security and poison the proxy cache and any     downstream caches with content from an arbitrary source. When configured for relaxed header parsing (the     default), Squid relays headers containing whitespace characters to upstream servers. When this occurs as a     prefix to a Content-Length header, the frame length specified will be ignored by Squid (allowing for a     conflicting length to be used from another Content-Length header) but relayed upstream.

    CVE-2020-15811:
    An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP     Request Splitting attacks may succeed against HTTP and HTTPS traffic. This leads to cache poisoning. This     allows any client, including browser scripts, to bypass local security and poison the browser cache and     any downstream caches with content from an arbitrary source. Squid uses a string search instead of parsing     the Transfer-Encoding header to find chunked encoding. This allows an attacker to hide a second request     inside Transfer-Encoding: it is interpreted by Squid as chunked and split out into a second request     delivered upstream. Squid will then deliver two distinct responses to the client, corrupting any     downstream caches.

    CVE-2020-24606:
    Squid before 4.13 and 5.x before 5.0.4 allows a trusted peer to perform Denial of Service by consuming all     available CPU cycles during handling of a crafted Cache Digest response message. This only occurs when     cache_peer is used with the cache digests feature. The problem exists because peerDigestHandleReply()     livelocking in peer_digest.cc mishandles EOF.

    CVE-2020-8449:
    An issue was discovered in Squid before 4.10. Due to incorrect input validation, it can interpret crafted     HTTP requests in unexpected ways to access server resources prohibited by earlier security filters.

    CVE-2020-8450:
    An issue was discovered in Squid before 4.10. Due to incorrect buffer management, a remote client can     cause a buffer overflow in a Squid instance acting as a reverse proxy.

Tenable has extracted the preceding description block directly from the Alibaba Cloud Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

This update for squid to version 4.11 fixes the following issues :

  - CVE-2020-11945: Fixed a potential remote code execution     vulnerability when using HTTP Digest Authentication     (bsc#1170313).

  - CVE-2019-12519, CVE-2019-12521: Fixed incorrect buffer     handling that can result in cache poisoning, remote     execution, and denial of service attacks when processing     ESI responses (bsc#1169659).

  - CVE-2020-8517: Fixed a possible denial of service caused     by incorrect buffer management ext_lm_group_acl when     processing NTLM Authentication credentials     (bsc#1162691).

  - CVE-2019-12528: Fixed possible information disclosure     when translating FTP server listings into HTTP responses     (bsc#1162689).

  - CVE-2019-18860: Fixed handling of invalid domain names     in cachemgr.cgi (bsc#1167373).

This update was imported from the SUSE:SLE-15:Update update project.

The remote Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-4356-1 advisory.

    Jeriko One discovered that Squid incorrectly handled certain Edge Side Includes (ESI) responses. A     malicious remote server could cause Squid to crash, possibly poison the cache, or possibly execute     arbitrary code. (CVE-2019-12519, CVE-2019-12521)

    It was discovered that Squid incorrectly handled the hostname parameter to cachemgr.cgi when certain     browsers are used. A remote attacker could possibly use this issue to inject HTML or invalid characters in     the hostname parameter. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 19.10.
    (CVE-2019-18860)

    Clment Berthaux and Florian Guilbert discovered that Squid incorrectly handled Digest Authentication     nonce values. A remote attacker could use this issue to replay nonce values, or possibly execute arbitrary     code. (CVE-2020-11945)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote host is affected by the vulnerability described in GLSA-202005-05 (Squid: Multiple vulnerabilities)

    Multiple vulnerabilities have been discovered in Squid. Please review       the CVE identifiers referenced below for details.
  Impact :

    Please review the referenced CVE identifiers for details.
  Workaround :

    There is no known workaround at this time.

This update for squid fixes the following issues :

CVE-2019-12519, CVE-2019-12521: fixes incorrect buffer handling that can result in cache poisoning, remote execution, and denial of service attacks when processing ESI responses (bsc#1169659).

CVE-2020-11945: fixes a potential remote execution vulnerability when using HTTP Digest Authentication (bsc#1170313).

CVE-2019-12520, CVE-2019-12524: fixes a potential ACL bypass, cache-bypass and cross-site scripting attack when processing invalid HTTP Request messages (bsc#1170423).

Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

According to the versions of the squid packages installed, the EulerOS installation on the remote host is affected by the following vulnerabilities :

  - Squid before 4.13 and 5.x before 5.0.4 allows a trusted     peer to perform Denial of Service by consuming all     available CPU cycles during handling of a crafted Cache     Digest response message. This only occurs when     cache_peer is used with the cache digests feature. The     problem exists because peerDigestHandleReply()     livelocking in peer_digest.cc mishandles     EOF.(CVE-2020-24606)

  - An issue was discovered in Squid through 4.7. When     handling the tag esi:when when ESI is enabled, Squid     calls ESIExpression::Evaluate. This function uses a     fixed stack buffer to hold the expression while it's     being evaluated. When processing the expression, it     could either evaluate the top of the stack, or add a     new member to the stack. When adding a new member,     there is no check to ensure that the stack won't     overflow.(CVE-2019-12519)

  - An issue was discovered in Squid through 4.7. When     Squid is parsing ESI, it keeps the ESI elements in     ESIContext. ESIContext contains a buffer for holding a     stack of ESIElements. When a new ESIElement is parsed,     it is added via addStackElement. addStackElement has a     check for the number of elements in this buffer, but     it's off by 1, leading to a Heap Overflow of 1 element.
    The overflow is within the same structure so it can't     affect adjacent memory blocks, and thus just leads to a     crash while processing.(CVE-2019-12521)

  - An issue was discovered in Squid before 5.0.2. A remote     attacker can replay a sniffed Digest Authentication     nonce to gain access to resources that are otherwise     forbidden. This occurs because the attacker can     overflow the nonce reference counter (a short integer).
    Remote code execution may occur if the pooled token     credentials are freed (instead of replayed as valid     credentials).(CVE-2020-11945)

  - An issue was discovered in Squid before 4.10. It allows     a crafted FTP server to trigger disclosure of sensitive     information from heap memory, such as information     associated with other users' sessions or non-Squid     processes.(CVE-2019-12528)

  - An issue was discovered in Squid before 4.10. Due to     incorrect input validation, it can interpret crafted     HTTP requests in unexpected ways to access server     resources prohibited by earlier security     filters.(CVE-2020-8449)

  - An issue was discovered in Squid before 4.10. Due to     incorrect buffer management, a remote client can cause     a buffer overflow in a Squid instance acting as a     reverse proxy.(CVE-2020-8450)

  - An issue was discovered in Squid before 4.10. Due to     incorrect input validation, the NTLM authentication     credentials parser in ext_lm_group_acl may write to     memory outside the credentials buffer. On systems with     memory access protections, this can result in the     helper process being terminated unexpectedly. This     leads to the Squid process also terminating and a     denial of service for all clients using the     proxy.(CVE-2020-8517)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The remote Oracle Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2020-4743 advisory.

  - An issue was discovered in Squid before 4.10. It allows a crafted FTP server to trigger disclosure of     sensitive information from heap memory, such as information associated with other users' sessions or non-     Squid processes. (CVE-2019-12528)

  - An issue was discovered in Squid before 4.10. Due to incorrect buffer management, a remote client can     cause a buffer overflow in a Squid instance acting as a reverse proxy. (CVE-2020-8450)

  - An issue was discovered in http/ContentLengthInterpreter.cc in Squid before 4.12 and 5.x before 5.0.3. A     Request Smuggling and Poisoning attack can succeed against the HTTP cache. The client sends an HTTP     request with a Content-Length header containing +\ - or an uncommon shell whitespace character prefix     to the length field-value. (CVE-2020-15049)

  - Squid before 4.13 and 5.x before 5.0.4 allows a trusted peer to perform Denial of Service by consuming all     available CPU cycles during handling of a crafted Cache Digest response message. This only occurs when     cache_peer is used with the cache digests feature. The problem exists because peerDigestHandleReply()     livelocking in peer_digest.cc mishandles EOF. (CVE-2020-24606)

  - An issue was discovered in Squid before 4.10. Due to incorrect input validation, it can interpret crafted     HTTP requests in unexpected ways to access server resources prohibited by earlier security filters.
    (CVE-2020-8449)

  - An issue was discovered in Squid through 4.7. When Squid is parsing ESI, it keeps the ESI elements in     ESIContext. ESIContext contains a buffer for holding a stack of ESIElements. When a new ESIElement is     parsed, it is added via addStackElement. addStackElement has a check for the number of elements in this     buffer, but it's off by 1, leading to a Heap Overflow of 1 element. The overflow is within the same     structure so it can't affect adjacent memory blocks, and thus just leads to a crash while processing.
    (CVE-2019-12521)

  - An issue was discovered in Squid before 4.9. When handling a URN request, a corresponding HTTP request is     made. This HTTP request doesn't go through the access checks that incoming HTTP requests go through. This     causes all access checks to be bypassed and allows access to restricted HTTP servers, e.g., an attacker     can connect to HTTP servers that only listen on localhost. (CVE-2019-12523)

  - An issue was discovered in Squid through 4.7. When handling requests from users, Squid checks its rules to     see if the request should be denied. Squid by default comes with rules to block access to the Cache     Manager, which serves detailed server information meant for the maintainer. This rule is implemented via     url_regex. The handler for url_regex rules URL decodes an incoming request. This allows an attacker to     encode their URL to bypass the url_regex check, and gain access to the blocked resource. (CVE-2019-12524)

  - An issue was discovered in Squid before 4.9. URN response handling in Squid suffers from a heap-based     buffer overflow. When receiving data from a remote server in response to an URN request, Squid fails to     ensure that the response can fit within the buffer. This leads to attacker controlled data overflowing in     the heap. (CVE-2019-12526)

  - An issue was discovered in Squid 2.x through 2.7.STABLE9, 3.x through 3.5.28, and 4.x through 4.7. When     Squid is configured to use Basic Authentication, the Proxy-Authorization header is parsed via uudecode.
    uudecode determines how many bytes will be decoded by iterating over the input and checking its table. The     length is then used to start decoding the string. There are no checks to ensure that the length it     calculates isn't greater than the input buffer. This leads to adjacent memory being decoded as well. An     attacker would not be able to retrieve the decoded data unless the Squid maintainer had configured the     display of usernames on error pages. (CVE-2019-12529)

  - Squid before 4.9, when certain web browsers are used, mishandles HTML in the host (aka hostname) parameter     to cachemgr.cgi. (CVE-2019-18860)

  - An issue was discovered in Squid before 4.12 and 5.x before 5.0.3. Due to use of a potentially dangerous     function, Squid and the default certificate validation helper are vulnerable to a Denial of Service when     opening a TLS connection to an attacker-controlled server for HTTPS. This occurs because unrecognized     error values are mapped to NULL, but later code expects that each error value is mapped to a valid error     string. (CVE-2020-14058)

  - An issue was discovered in Squid through 4.7 and 5. When receiving a request, Squid checks its cache to     see if it can serve up a response. It does this by making a MD5 hash of the absolute URL of the request.
    If found, it servers the request. The absolute URL can include the decoded UserInfo (username and     password) for certain protocols. This decoded info is prepended to the domain. This allows an attacker to     provide a username that has special characters to delimit the domain, and treat the rest of the URL as a     path or query string. An attacker could first make a request to their domain using an encoded username,     then when a request for the target domain comes in that decodes to the exact URL, it will serve the     attacker's HTML instead of the real HTML. On Squid servers that also act as reverse proxies, this allows     an attacker to gain access to features that only reverse proxies can use, such as ESI. (CVE-2019-12520)

  - Due to incorrect string termination, Squid cachemgr.cgi 4.0 through 4.7 may access unallocated memory. On     systems with memory access protections, this can cause the CGI process to terminate unexpectedly,     resulting in a denial of service for all clients using it. (CVE-2019-12854)

  - An issue was discovered in Squid 3.x and 4.x through 4.8. Due to incorrect input validation, there is a     heap-based buffer overflow that can result in Denial of Service to all clients using the proxy. Severity     is high due to this vulnerability occurring before normal security checks; any remote client that can     reach the proxy port can trivially perform the attack via a crafted URI scheme. (CVE-2019-18676)

  - An issue was discovered in Squid 3.x and 4.x through 4.8 when the append_domain setting is used (because     the appended characters do not properly interact with hostname length restrictions). Due to incorrect     message processing, it can inappropriately redirect traffic to origins it should not be delivered to.
    (CVE-2019-18677)

  - An issue was discovered in Squid 3.x and 4.x through 4.8. It allows attackers to smuggle HTTP requests     through frontend software to a Squid instance that splits the HTTP Request pipeline differently. The     resulting Response messages corrupt caches (between a client and Squid) with attacker-controlled content     at arbitrary URLs. Effects are isolated to software between the attacker client and Squid. There are no     effects on Squid itself, nor on any upstream servers. The issue is related to a request header containing     whitespace between a header name and a colon. (CVE-2019-18678)

  - An issue was discovered in Squid 2.x, 3.x, and 4.x through 4.8. Due to incorrect data management, it is     vulnerable to information disclosure when processing HTTP Digest Authentication. Nonce tokens contain the     raw byte value of a pointer that sits within heap memory allocation. This information reduces ASLR     protections and may aid attackers isolating memory areas to target for remote code execution attacks.
    (CVE-2019-18679)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLES11 host has a package installed that is affected by multiple vulnerabilities as referenced in the SUSE-SU-2020:14460-1 advisory.

  - An issue was discovered in Squid through 4.7. When handling the tag esi:when when ESI is enabled, Squid     calls ESIExpression::Evaluate. This function uses a fixed stack buffer to hold the expression while it's     being evaluated. When processing the expression, it could either evaluate the top of the stack, or add a     new member to the stack. When adding a new member, there is no check to ensure that the stack won't     overflow. (CVE-2019-12519)

  - An issue was discovered in Squid through 4.7 and 5. When receiving a request, Squid checks its cache to     see if it can serve up a response. It does this by making a MD5 hash of the absolute URL of the request.
    If found, it servers the request. The absolute URL can include the decoded UserInfo (username and     password) for certain protocols. This decoded info is prepended to the domain. This allows an attacker to     provide a username that has special characters to delimit the domain, and treat the rest of the URL as a     path or query string. An attacker could first make a request to their domain using an encoded username,     then when a request for the target domain comes in that decodes to the exact URL, it will serve the     attacker's HTML instead of the real HTML. On Squid servers that also act as reverse proxies, this allows     an attacker to gain access to features that only reverse proxies can use, such as ESI. (CVE-2019-12520)

  - An issue was discovered in Squid through 4.7. When Squid is parsing ESI, it keeps the ESI elements in     ESIContext. ESIContext contains a buffer for holding a stack of ESIElements. When a new ESIElement is     parsed, it is added via addStackElement. addStackElement has a check for the number of elements in this     buffer, but it's off by 1, leading to a Heap Overflow of 1 element. The overflow is within the same     structure so it can't affect adjacent memory blocks, and thus just leads to a crash while processing.
    (CVE-2019-12521)

  - An issue was discovered in Squid before 4.9. When handling a URN request, a corresponding HTTP request is     made. This HTTP request doesn't go through the access checks that incoming HTTP requests go through. This     causes all access checks to be bypassed and allows access to restricted HTTP servers, e.g., an attacker     can connect to HTTP servers that only listen on localhost. (CVE-2019-12523)

  - An issue was discovered in Squid through 4.7. When handling requests from users, Squid checks its rules to     see if the request should be denied. Squid by default comes with rules to block access to the Cache     Manager, which serves detailed server information meant for the maintainer. This rule is implemented via     url_regex. The handler for url_regex rules URL decodes an incoming request. This allows an attacker to     encode their URL to bypass the url_regex check, and gain access to the blocked resource. (CVE-2019-12524)

  - An issue was discovered in Squid 3.3.9 through 3.5.28 and 4.x through 4.7. When Squid is configured to use     Digest authentication, it parses the header Proxy-Authorization. It searches for certain tokens such as     domain, uri, and qop. Squid checks if this token's value starts with a quote and ends with one. If so, it     performs a memcpy of its length minus 2. Squid never checks whether the value is just a single quote     (which would satisfy its requirements), leading to a memcpy of its length minus 1. (CVE-2019-12525)

  - An issue was discovered in Squid before 4.9. URN response handling in Squid suffers from a heap-based     buffer overflow. When receiving data from a remote server in response to an URN request, Squid fails to     ensure that the response can fit within the buffer. This leads to attacker controlled data overflowing in     the heap. (CVE-2019-12526)

  - An issue was discovered in Squid before 4.10. It allows a crafted FTP server to trigger disclosure of     sensitive information from heap memory, such as information associated with other users' sessions or non-     Squid processes. (CVE-2019-12528)

  - An issue was discovered in Squid 2.x through 2.7.STABLE9, 3.x through 3.5.28, and 4.x through 4.7. When     Squid is configured to use Basic Authentication, the Proxy-Authorization header is parsed via uudecode.
    uudecode determines how many bytes will be decoded by iterating over the input and checking its table. The     length is then used to start decoding the string. There are no checks to ensure that the length it     calculates isn't greater than the input buffer. This leads to adjacent memory being decoded as well. An     attacker would not be able to retrieve the decoded data unless the Squid maintainer had configured the     display of usernames on error pages. (CVE-2019-12529)

  - The cachemgr.cgi web module of Squid through 4.7 has XSS via the user_name or auth parameter.
    (CVE-2019-13345)

  - An issue was discovered in Squid 3.x and 4.x through 4.8. Due to incorrect input validation, there is a     heap-based buffer overflow that can result in Denial of Service to all clients using the proxy. Severity     is high due to this vulnerability occurring before normal security checks; any remote client that can     reach the proxy port can trivially perform the attack via a crafted URI scheme. (CVE-2019-18676)

  - An issue was discovered in Squid 3.x and 4.x through 4.8 when the append_domain setting is used (because     the appended characters do not properly interact with hostname length restrictions). Due to incorrect     message processing, it can inappropriately redirect traffic to origins it should not be delivered to.
    (CVE-2019-18677)

  - An issue was discovered in Squid 3.x and 4.x through 4.8. It allows attackers to smuggle HTTP requests     through frontend software to a Squid instance that splits the HTTP Request pipeline differently. The     resulting Response messages corrupt caches (between a client and Squid) with attacker-controlled content     at arbitrary URLs. Effects are isolated to software between the attacker client and Squid. There are no     effects on Squid itself, nor on any upstream servers. The issue is related to a request header containing     whitespace between a header name and a colon. (CVE-2019-18678)

  - An issue was discovered in Squid 2.x, 3.x, and 4.x through 4.8. Due to incorrect data management, it is     vulnerable to information disclosure when processing HTTP Digest Authentication. Nonce tokens contain the     raw byte value of a pointer that sits within heap memory allocation. This information reduces ASLR     protections and may aid attackers isolating memory areas to target for remote code execution attacks.
    (CVE-2019-18679)

  - Squid before 4.9, when certain web browsers are used, mishandles HTML in the host (aka hostname) parameter     to cachemgr.cgi. (CVE-2019-18860)

  - An issue was discovered in Squid before 5.0.2. A remote attacker can replay a sniffed Digest     Authentication nonce to gain access to resources that are otherwise forbidden. This occurs because the     attacker can overflow the nonce reference counter (a short integer). Remote code execution may occur if     the pooled token credentials are freed (instead of replayed as valid credentials). (CVE-2020-11945)

  - An issue was discovered in Squid 5.x before 5.0.3. Due to an Incorrect Synchronization, a Denial of     Service can occur when processing objects in an SMP cache because of an Ipc::Mem::PageStack::pop ABA     problem during access to the memory page/slot management list. (CVE-2020-14059)

  - An issue was discovered in http/ContentLengthInterpreter.cc in Squid before 4.12 and 5.x before 5.0.3. A     Request Smuggling and Poisoning attack can succeed against the HTTP cache. The client sends an HTTP     request with a Content-Length header containing +\ - or an uncommon shell whitespace character prefix     to the length field-value. (CVE-2020-15049)

  - An issue was discovered in Squid before 4.10. Due to incorrect input validation, it can interpret crafted     HTTP requests in unexpected ways to access server resources prohibited by earlier security filters.
    (CVE-2020-8449)

  - An issue was discovered in Squid before 4.10. Due to incorrect buffer management, a remote client can     cause a buffer overflow in a Squid instance acting as a reverse proxy. (CVE-2020-8450)

  - An issue was discovered in Squid before 4.10. Due to incorrect input validation, the NTLM authentication     credentials parser in ext_lm_group_acl may write to memory outside the credentials buffer. On systems with     memory access protections, this can result in the helper process being terminated unexpectedly. This leads     to the Squid process also terminating and a denial of service for all clients using the proxy.
    (CVE-2020-8517)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The version of squid installed on the remote host is prior to 4.11-1. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2SQUID4-2023-008 advisory.

    A flaw was found in Squid through version 4.7. When handling the tag esi:when, when ESI is enabled, Squid     calls the ESIExpression::Evaluate function which uses a fixed stack buffer to hold the expression. While     processing the expression, there is no check to ensure that the stack won't overflow. The highest threat     from this vulnerability is to data confidentiality and integrity as well as system availability.
    (CVE-2019-12519)

    A flaw was found in squid. When Squid is parsing ESI, it keeps the ESI elements in ESIContext. ESIContext     contains a buffer for holding a stack of ESIElements. When a new ESIElement is parsed, it is added via     addStackElement. addStackElement has a check for the number of elements in this buffer, but it's off by 1,     leading to a Heap Overflow of 1 element. The overflow is within the same structure so it can't affect     adjacent memory blocks, and thus just leads to a crash while processing. (CVE-2019-12521)

    An issue was discovered in Squid 3.3.9 through 3.5.28 and 4.x through 4.7. When Squid is configured to use     Digest authentication, it parses the header Proxy-Authorization. It searches for certain tokens such as     domain, uri, and qop. Squid checks if this token's value starts with a quote and ends with one. If so, it     performs a memcpy of its length minus 2. Squid never checks whether the value is just a single quote     (which would satisfy its requirements), leading to a memcpy of its length minus 1. (CVE-2019-12525)

    A flaw was found in Squid, where a remote attacker can replay a sniffed Digest Authentication nonce to     gain access to resources that are otherwise forbidden. This issue occurs because the attacker can overflow     the nonce reference counter, which results in remote code execution if the pooled token credentials are     freed. (CVE-2020-11945)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of squid installed on the remote host is prior to 3.5.20-17. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2024-2509 advisory.

    A flaw was found in squid. When Squid is parsing ESI, it keeps the ESI elements in ESIContext. ESIContext     contains a buffer for holding a stack of ESIElements. When a new ESIElement is parsed, it is added via     addStackElement. addStackElement has a check for the number of elements in this buffer, but it's off by 1,     leading to a Heap Overflow of 1 element. The overflow is within the same structure so it can't affect     adjacent memory blocks, and thus just leads to a crash while processing. (CVE-2019-12521)

    Due to chunked decoder lenience Squid is vulnerable to Request/Response smuggling attacks when parsing     HTTP/1.1 and ICAP messages. (CVE-2023-46846)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	名称	产品	系列	发布时间	最近更新时间	严重程度
181963	Amazon Linux 2：squid (ALASSQUID4-2023-008)	Nessus	Amazon Linux Local Security Checks	2023/9/27	2024/12/11	critical
180917	Oracle Linux 8：squid: 4 (ELSA-2020-4743)	Nessus	Oracle Linux Local Security Checks	2023/9/7	2023/9/7	critical
184691	Rocky Linux 8 : squid:4 (RLSA-2020:4743)	Nessus	Rocky Linux Local Security Checks	2023/11/6	2023/11/6	critical
136430	Debian DSA-4682-1 : squid - security update	Nessus	Debian Local Security Checks	2020/5/11	2024/3/13	critical
142412	RHEL 8 : squid:4 (RHSA-2020:4743)	Nessus	Red Hat Local Security Checks	2020/11/4	2024/11/7	critical
222577	Linux Distros Unpatched Vulnerability : CVE-2019-12521	Nessus	Misc.	2025/3/4	2025/8/20	medium
236441	Alibaba Cloud Linux 3 : 0124: squid:4 (ALINUX3-SA-2022:0124)	Nessus	Alibaba Cloud Linux Local Security Checks	2025/5/14	2025/5/14	critical
136452	openSUSE Security Update : squid (openSUSE-2020-623)	Nessus	SuSE Local Security Checks	2020/5/11	2024/3/13	critical
136605	Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS : Squid vulnerabilities (USN-4356-1)	Nessus	Ubuntu Local Security Checks	2020/5/14	2025/9/3	critical
136542	GLSA-202005-05 : Squid: Multiple vulnerabilities	Nessus	Gentoo Local Security Checks	2020/5/13	2024/3/12	critical
136659	SUSE SLES12 Security Update : squid (SUSE-SU-2020:1227-1)	Nessus	SuSE Local Security Checks	2020/5/15	2024/3/12	critical
140894	EulerOS 2.0 SP3 : squid (EulerOS-SA-2020-2127)	Nessus	Huawei Local Security Checks	2020/9/28	2022/5/12	critical
180917	Oracle Linux 8 : squid:4 (ELSA-2020-4743)	Nessus	Oracle Linux Local Security Checks	2023/9/7	2023/9/7	critical
150657	SUSE SLES11 Security Update : squid3 (SUSE-SU-2020:14460-1)	Nessus	SuSE Local Security Checks	2021/6/10	2023/12/26	critical
181963	Amazon Linux 2 : squid (ALASSQUID4-2023-008)	Nessus	Amazon Linux Local Security Checks	2023/9/27	2024/12/11	critical
192745	Amazon Linux 2 : squid (ALAS-2024-2509)	Nessus	Amazon Linux Local Security Checks	2024/4/1	2024/12/11	medium

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