Release date: 
Friday, February 5, 2021 - 12:17
squid:4 security, bug fix, enhancement update
Affected Channels: 
Asianux Server 8 for x86_64

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).

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.

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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Squid before 4.9, when certain web browsers are used, mishandles HTML in the host (aka hostname) parameter to cachemgr.cgi.
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.
An issue was discovered in http/ 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.
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 mishandles EOF.
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.
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.

Modularity name: squid
Stream name: 4


Update packages.

Additional Info: 



  1. libecap-1.0.1-2.module+el8+1170+19b6248b.src.rpm
    MD5: 029b419ec78d7c25892f5f2f0977b33c
    SHA-256: 900d8533a5495b4a42c1f7c99ea152fe517b1cae80c86ccb9c4cbed69da93756
    Size: 343.58 kB
  2. squid-4.11-3.module+el8+1170+19b6248b.src.rpm
    MD5: 1d9016fb34a6c485b13bbff9f02f7238
    SHA-256: 7eb22c196ec1744e04afa2e1f39dd8fbd97bb7fc0c3fa8e4e5099aab6c969b69
    Size: 2.42 MB

Asianux Server 8 for x86_64
  1. libecap-1.0.1-2.module+el8+1170+19b6248b.x86_64.rpm
    MD5: 7d2b5776f2c8dfccdb55b75e72479f33
    SHA-256: ef8c559edfade6fab8e2af452ec29731272ce995c3d8de2d83202c81b308e81e
    Size: 27.79 kB
  2. libecap-debugsource-1.0.1-2.module+el8+1170+19b6248b.x86_64.rpm
    MD5: 68ea2c0d1d934c546e79086d8274ece1
    SHA-256: b424fc9a996205ef5882adedf6083c4dd2591f458c41ce241a93b82a84b2bdd2
    Size: 18.92 kB
  3. libecap-devel-1.0.1-2.module+el8+1170+19b6248b.x86_64.rpm
    MD5: e8ac65430a390b6b33cb289291f4e8b8
    SHA-256: cd753d9d4fa50be5c14f1b5375d91e5bcd2333d6e820f265d9e26b804b9421d4
    Size: 20.45 kB
  4. squid-4.11-3.module+el8+1170+19b6248b.x86_64.rpm
    MD5: 1f9f03febe38db831b6a160d59aa7289
    SHA-256: 21236e18bb4c42c05858dcd1251089d5e03cd438c4342aa2133345abee9dfdf8
    Size: 3.56 MB
  5. squid-debugsource-4.11-3.module+el8+1170+19b6248b.x86_64.rpm
    MD5: d705eefd78b5303c094f9aee1ec7c4a8
    SHA-256: a1bdd618c2176ca4537f9500aa66082b7353325f63587d5f586d1bc9c6588311
    Size: 1.73 MB
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