Vulnerabilities > CVE-2020-24606 - Improper Locking vulnerability in multiple products
Attack vector
NETWORK Attack complexity
LOW Privileges required
NONE Confidentiality impact
NONE Integrity impact
NONE Availability impact
HIGH Summary
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.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Leveraging Race Conditions This attack targets a race condition occurring when multiple processes access and manipulate the same resource concurrently and the outcome of the execution depends on the particular order in which the access takes place. The attacker can leverage a race condition by "running the race", modifying the resource and modifying the normal execution flow. For instance a race condition can occur while accessing a file, the attacker can trick the system by replacing the original file with his version and cause the system to read the malicious file.
- Leveraging Race Conditions via Symbolic Links This attack leverages the use of symbolic links (Symlinks) in order to write to sensitive files. An attacker can create a Symlink link to a target file not otherwise accessible to her. When the privileged program tries to create a temporary file with the same name as the Symlink link, it will actually write to the target file pointed to by the attackers' Symlink link. If the attacker can insert malicious content in the temporary file she will be writing to the sensitive file by using the Symlink. The race occurs because the system checks if the temporary file exists, then creates the file. The attacker would typically create the Symlink during the interval between the check and the creation of the temporary file.
References
- http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00012.html
- http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00012.html
- http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00017.html
- http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00017.html
- http://www.squid-cache.org/Versions/v4/changesets/SQUID-2020_9.patch
- http://www.squid-cache.org/Versions/v4/changesets/SQUID-2020_9.patch
- https://github.com/squid-cache/squid/security/advisories/GHSA-vvj7-xjgq-g2jg
- https://github.com/squid-cache/squid/security/advisories/GHSA-vvj7-xjgq-g2jg
- https://lists.debian.org/debian-lts-announce/2020/10/msg00005.html
- https://lists.debian.org/debian-lts-announce/2020/10/msg00005.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BE6FKUN7IGTIR2MEEMWYDT7N5EJJLZI2/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BE6FKUN7IGTIR2MEEMWYDT7N5EJJLZI2/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BMTFLVB7GLRF2CKGFPZ4G4R5DIIPHWI3/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BMTFLVB7GLRF2CKGFPZ4G4R5DIIPHWI3/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HJJDI7JQFGQLVNCKMVY64LAFMKERAOK7/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HJJDI7JQFGQLVNCKMVY64LAFMKERAOK7/
- https://security.netapp.com/advisory/ntap-20210219-0007/
- https://security.netapp.com/advisory/ntap-20210219-0007/
- https://security.netapp.com/advisory/ntap-20210226-0006/
- https://security.netapp.com/advisory/ntap-20210226-0006/
- https://security.netapp.com/advisory/ntap-20210226-0007/
- https://security.netapp.com/advisory/ntap-20210226-0007/
- https://usn.ubuntu.com/4477-1/
- https://usn.ubuntu.com/4477-1/
- https://usn.ubuntu.com/4551-1/
- https://usn.ubuntu.com/4551-1/
- https://www.debian.org/security/2020/dsa-4751
- https://www.debian.org/security/2020/dsa-4751