CVE-2021-32687 is a high-severity integer overflow vulnerability in Redis, an open source, in-memory database that persists on disk. This vulnerability allows an attacker to exploit the system by changing the default set-max-intset-entries configuration parameter to a very large value. Such an action can lead to heap corruption and potentially allow the attacker to leak arbitrary contents of the heap or trigger remote code execution. The problem is fixed in Redis versions 6.2.6, 6.0.16, and 5.0.14. Organizations should prioritize patching immediately to mitigate potential risks, including remote code execution.
The vulnerability was published on October 4, 2021, and continues to pose a significant risk to organizations that have not yet implemented the necessary patches. Given the attack vector is network-based and the complexity is rated as high, organizations should be aware of the potential impact on their systems and prioritize remediation efforts accordingly.
As of now, there is no public exploit confirmed, though the vulnerability's nature suggests that it could be actively exploited if not addressed. The urgency for defenders cannot be overstated, especially considering the potential for remote code execution which could compromise sensitive data and system integrity.
Given the implications of this vulnerability, organizations should ensure that they have appropriate controls in place to prevent unprivileged users from modifying the configuration parameter. Utilizing Access Control Lists (ACLs) to restrict access to the CONFIG SET command can serve as an effective workaround while awaiting the application of formal patches.
Vulnerability Details
The official CVE description states: "Redis is an open source, in-memory database that persists on disk. An integer overflow bug affecting all versions of Redis can be exploited to corrupt the heap and potentially be used to leak arbitrary contents of the heap or trigger remote code execution." The vulnerability has a CVSS score of 7.5, indicating high severity.
The affected product includes all versions of Redis prior to the fixed versions. This includes notable versions such as 6.2.5 and earlier, 6.0.15 and earlier, and 5.0.13 and earlier. The vulnerability falls under the CWE classifications of CWE-190 (Integer Overflow or Wraparound) and CWE-680 (Integer Overflow to Buffer Overflow), highlighting the critical nature of the issue.
Technical Analysis
The root cause of CVE-2021-32687 is an integer overflow issue that arises when the default set-max-intset-entries configuration parameter is manipulated. The attack vector is network-based, with a high complexity level required to exploit the vulnerability. The privileges required for exploitation are low, and no user interaction is necessary.
The attack can lead to significant impacts on confidentiality, integrity, and availability, as it allows for the potential execution of arbitrary code, thus compromising the security of the affected systems.
Risk & Impact Analysis
Organizations running vulnerable versions of Redis face substantial risks. The potential for remote code execution means that attackers could gain unauthorized access to sensitive data, leading to data breaches and significant reputational damage. The blast radius for this vulnerability is considerable, impacting not just the Redis instances but potentially other interconnected systems.
With a CVSS score of 7.5, urgent action is required. Organizations should address this vulnerability as part of their priority patch cycle to mitigate the risk of exploitation. The EPSS score indicates a low probability of exploitation, but the consequences of a successful attack could be severe.
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
All versions of Redis prior to 6.2.6, 6.0.16, and 5.0.14 are affected by this vulnerability. This includes various distributions such as Debian, Fedora, and Oracle software that use Redis as part of their stack.
Mitigation & Remediation
To mitigate this vulnerability, organizations should apply the relevant patches available for Redis. The fixed versions include Redis 6.2.6, 6.0.16, and 5.0.14. If patching is not immediately feasible, organizations can restrict access to the CONFIG SET command using ACL to prevent users from modifying the set-max-intset-entries configuration parameter.
For further security measures, organizations can implement network controls to limit access to Redis services only from trusted IP addresses and monitor for any anomalous behavior that may indicate attempts to exploit this vulnerability.
For comprehensive security testing and vulnerability management, organizations should consider engaging in regular penetration testing to identify and remediate similar vulnerabilities.
Detection Guidance
Organizations should monitor logs for any suspicious activity or unauthorized access attempts to Redis instances. Behavioral anomalies, such as unusual commands being executed or changes to configuration parameters, should be flagged for further investigation.
Network signatures can also be established to identify potential exploitation attempts related to this vulnerability.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-32687 lies in its demonstration of the risks associated with integer overflow vulnerabilities, particularly in widely-used software like Redis. Security teams should take note of this vulnerability as a case study in how configuration parameters can be exploited and should enhance their defensive strategies to include proactive monitoring and strict configuration management.
Recognizing patterns in such vulnerabilities can help organizations anticipate future risks and implement more robust security controls. For teams looking to improve their security posture, resources on vulnerability management programs and effective penetration testing methodologies can provide valuable insights.
Ultimately, organizations should integrate lessons learned from vulnerabilities like CVE-2021-32687 into their security culture, fostering an environment where security is prioritized and continuously improved.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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