CVE-2021-28652
Description
A flaw was found in Squid. A parser validation bug could allow a trusted client with Cache Manager API access privileges to trigger memory leaks, potentially resulting in a denial of service against Squid. The highest threat from this vulnerability is to system availability.
Statement
This issue has been rated as having a security impact of Moderate. At this stage in their life, Red Hat Enterprise Linux 6 and 7 only accept Important and Critical Security Advisories (RHSAs) and this flaw does not meet these criteria. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata.
Red Hat Satellite does not ship the Squid package, however, does consume it from RHEL 7 repository. Product is not affected by this flaw as squid.conf configuration disables all the http_access fragments except the localhost.
Mitigation
To mitigate this flaw Cache Manager access privileges can be hardened, for example by requiring authentication or other access controls in the "http_access" directive beyond the default IP address restriction. Alternatively, Cache Manager access can be disabled entirely if not needed. To do so, place the following line in `squid.conf` before lines containing "allow" :
http_access deny manager
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.8 | 4.9 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | High | High | N/A |
| User Interaction | None | None | N/A |
| Scope | Changed | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Instability; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
Most memory leaks result in general product reliability problems, but if an attacker can intentionally trigger a memory leak, the attacker might be able to launch a denial of service attack (by crashing or hanging the program) or take advantage of other unexpected program behavior resulting from a low memory condition.
Other
Technical Impact: Reduce Performance
Acknowledgements
Upstream acknowledges Joshua Rogers (Opera Software) as the original reporter.
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