An issue was discovered in Squid before 4.15 and 5.x before 5.0.6. Due to incorrect parser validation, it allows a Denial of Service attack against the Cache Manager API. This allows a trusted client to trigger memory leaks that, over time, lead to a Denial of Service via an unspecified short query string. This attack is limited to clients with Cache Manager API access privilege.
The vulnerability carries a CVSS score of 4.9, categorizing it as medium severity. Organizations running affected versions are at risk of service disruption, which could affect availability and operational capability.
Given the potential impact of this vulnerability, organizations should prioritize patching immediately. Failure to address this issue may lead to significant resource strain and service degradation.
The vulnerability has not been confirmed to have any known exploits in the wild. However, the presence of the flaw itself necessitates immediate attention to mitigate risks associated with denial of service.
Vulnerability Details
CVE-2021-28652 affects Squid versions prior to 4.15 and 5.x before 5.0.6. The flaw arises from improper parser validation, leading to a Denial of Service vulnerability on the Cache Manager API. This vulnerability is classified under CWE-401.
The attack vector for this vulnerability is network-based, requiring high privileges to exploit. It has a low attack complexity and does not require user interaction. The impact on availability is classified as high, while confidentiality and integrity impacts are negligible.
Technical Analysis
The root cause of the vulnerability lies in improper validation within the parser, which fails to handle certain input conditions correctly. Attackers can exploit this by sending specially crafted requests that trigger memory leaks, eventually leading to service unavailability.
The vulnerability is categorized as having a low attack complexity, meaning that attackers can easily exploit it if they have the necessary access privileges. The requirement for high privileges indicates that only users with specific access rights to the Cache Manager API can initiate this attack.
Risk & Impact Analysis
Risk to organizations includes potential service outages and resource exhaustion, which can disrupt normal operations. Given the nature of the vulnerability, it is crucial for organizations to evaluate the blast radius of this flaw within their infrastructure.
The urgency for remediation is classified as high due to the medium severity score and the potential for significant availability impact. Organizations should schedule remediation as soon as possible to mitigate any risks associated with this vulnerability.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The following versions of Squid are affected by this vulnerability:
Squid versions prior to 4.15 and 5.x before 5.0.6 are vulnerable. Organizations should ensure they are running the patched versions to avoid exploitation.
Mitigation & Remediation
Organizations should apply the latest patches from their respective distributions. For Debian users, security updates are available through the standard update process. Fedora users should also ensure their installations are up to date.
In addition to patching, organizations should monitor their systems for unusual activity and consider implementing additional network controls to limit access to the Cache Manager API.
Continuous penetration testing can help identify weaknesses associated with this vulnerability.
Detection Guidance
Monitoring for abnormal usage patterns or spikes in memory consumption can be indicative of an attack attempting to exploit this vulnerability. Additionally, organizations should review logs for unauthorized access attempts to the Cache Manager API.
AppSecure Threat Intelligence Insight
The long-term significance of this vulnerability lies in the potential for denial of service attacks, which can severely impact service availability. Organizations should remain vigilant and proactively address vulnerabilities to mitigate risks.
This vulnerability represents a broader trend in which misconfigurations and improper validations lead to exploitable conditions. Security teams should prioritize improving validation processes within their applications.
For further reading on vulnerability management and security best practices, organizations can refer to the following resources:
Vulnerability management program design and penetration testing methodology are key components in strengthening security posture.
By addressing this vulnerability promptly and implementing robust security measures, organizations can safeguard their infrastructure from potential attacks.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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