CVE-2021-28651 is a high-severity vulnerability affecting Squid versions prior to 4.15 and those in the 5.x series before 5.0.6. This vulnerability allows for denial of service due to a buffer-management bug that can lead to significant memory consumption. The issue arises when resolving a request with the urn: scheme, causing the parser to leak a small amount of memory, but with an unspecified attack methodology, it can trigger much larger memory usage. Organizations must address this issue promptly to prevent system outages.
The vulnerability has a CVSS score of 7.5, indicating a high level of risk. Its exploitation could lead to severe availability impacts, which is critical for organizations relying on Squid for caching and proxy services. As the vulnerability status has been modified, it is essential to stay updated with the latest patches and advisories from the vendor.
Currently, there are no confirmed public exploits for this vulnerability. However, the potential for denial of service attacks necessitates immediate attention from security teams to safeguard their systems. Organizations should prioritize patching immediately to mitigate risk and ensure the stability and reliability of their services.
In light of this vulnerability, it is crucial for organizations to assess their current deployments of Squid and implement necessary updates. The urgency of this issue cannot be overstated, as the impact on availability could disrupt critical services.
Vulnerability Details
CVE-2021-28651 is characterized by a buffer-management bug in Squid, which allows for denial of service. The vulnerability was published on May 27, 2021, and affects all versions prior to 4.15 and 5.x before 5.0.6. The CWEs associated with this vulnerability include CWE-401, which refers to memory leaks. Organizations using affected versions of Squid must act swiftly to patch their systems.
Technical Analysis
The root cause of this vulnerability is a buffer-management bug that leads to memory leaks during the processing of requests using the urn: scheme. Attackers can exploit this vulnerability via the network, as it requires no privileges or user interaction, making the attack vector particularly dangerous. The attack complexity is low, indicating that it can be executed without substantial effort. The impact on availability is high, which poses a significant risk to organizations relying on Squid for proxy services. The confidentiality and integrity impacts are reported as none, but the potential for availability disruption should not be underestimated.
Risk & Impact Analysis
The risk to organizations includes potential outages of services relying on Squid for caching and proxy functionality. This vulnerability can be exploited easily and may result in substantial memory consumption, leading to denial of service. The blast radius is significant, as many organizations use Squid in critical infrastructure roles. Given the high CVSS score of 7.5 and the lack of public exploits, organizations should evaluate their current configurations and prioritize patching in their remediation cycles.
Organizations should address in priority patch cycle and ensure they have suitable monitoring in place to detect any unusual behavior that could indicate exploitation attempts. The urgency is compounded by the potential for widespread impact across various sectors relying on Debian, Fedora, and NetApp products.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions include Squid versions prior to 4.15 and those in the 5.x series before 5.0.6. Additionally, Debian Linux 9.0 and 10.0, Fedora 33 and 34, and NetApp's Cloud Manager are also impacted. Organizations should ensure they are using patched and updated versions to mitigate risks associated with this vulnerability.
Mitigation & Remediation
Organizations should prioritize upgrading to the latest versions of Squid, specifically version 5.0.6 or later and 4.15 or later to resolve this vulnerability. If immediate patching is not possible, temporary mitigations may include implementing rate limiting and monitoring network traffic for unusual patterns that could indicate exploitation attempts. Regular audits and assessments of configurations can enhance resilience against such vulnerabilities.
For more comprehensive security measures, organizations should consider engaging in penetration testing to validate the effectiveness of their security controls.
Detection Guidance
To detect potential exploitation of this vulnerability, organizations should monitor logs for error messages related to memory allocation failures and unusual spikes in memory usage. Additionally, behavioral anomalies in network traffic, especially involving requests using the urn: scheme, should be investigated. Implementing network signatures that identify patterns indicative of this vulnerability can enhance detection capabilities.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-28651 lies in its reflection of vulnerabilities that can arise from buffer-management issues, a common flaw in many software systems. This vulnerability underscores the importance of rigorous memory management practices in software development and the necessity for regular security audits. Security teams must remain vigilant in monitoring their environments for similar vulnerabilities and ensure that they are employing best practices in coding and architecture to prevent exploitation.
Organizations can benefit from reviewing their security strategies against the backdrop of such vulnerabilities and should consider penetration testing methodologies to enhance their defenses. The evolving nature of cyber threats requires a proactive approach to security that includes continuous monitoring and assessment.
Furthermore, integrating threat intelligence can provide valuable insights into emerging vulnerabilities and attack patterns, enabling organizations to stay ahead of potential threats. Continuous improvement in security posture through vulnerability management programs will be essential for maintaining robust defenses.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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