CVE-2021-32628 is a high-severity vulnerability affecting Redis, an open-source in-memory database. The issue arises from an integer overflow bug in the ziplist data structure used by all versions of Redis. This vulnerability allows attackers to corrupt the heap, potentially resulting in remote code execution. The vulnerability specifically involves modifying the default ziplist configuration parameters, including hash-max-ziplist-entries, hash-max-ziplist-value, zset-max-ziplist-entries, or zset-max-ziplist-value to excessively large values. Subsequently, specially crafted commands can create very large ziplists, leading to exploitation.
The CVSS score for this vulnerability is 7.5, categorizing it as high severity. This score indicates significant risks to organizations, especially given the network attack vector and the low privileges required for exploitation. The vulnerability was published on October 4, 2021, and remains relevant as organizations continue to use affected versions of Redis.
Organizations using Redis should prioritize patching immediately. The vulnerability has been addressed in Redis versions 6.2.6, 6.0.16, and 5.0.14. For those unable to apply the patch immediately, it is recommended to restrict users from modifying the aforementioned configuration parameters through Access Control Lists (ACLs), effectively mitigating the exploitation risk.
As of now, there is no confirmed public exploit available for this vulnerability. However, the potential for remote code execution emphasizes the need for swift remediation efforts. Organizations must remain vigilant and informed on this matter.
Vulnerability Details
The official description of CVE-2021-32628 states that Redis is an open-source, in-memory database that persists on disk. An integer overflow bug in the ziplist data structure can be exploited to corrupt the heap, leading to possible remote code execution. The affected versions of Redis include all versions prior to the fixes provided in 6.2.6, 6.0.16, and 5.0.14. The vulnerability is classified under CWE-190 and CWE-680, representing integer overflow and improper handling of exceptional conditions, respectively.
The CVSS 3.1 score for this vulnerability is 7.5, indicating a high severity level. The attack vector is classified as NETWORK, with high attack complexity, low privileges required, and no user interaction necessary to exploit the vulnerability. The potential impacts include high confidentiality, integrity, and availability impacts.
Technical Analysis
The root cause of CVE-2021-32628 is an integer overflow occurring in the ziplist data structure of Redis. This vulnerability can be exploited through a remote attack, making it particularly dangerous. The attack complexity is considered high due to the requirement to construct specially crafted commands, and it necessitates low privileges for the attacker. Importantly, no user interaction is required for the attack to succeed. The impacts on confidentiality, integrity, and availability are all rated as high, highlighting the serious nature of this vulnerability.
Risk & Impact Analysis
Risk to organizations includes significant potential damage from remote code execution. The high CVSS score indicates that this vulnerability should be addressed urgently, particularly given the ease of exploitation and the potential for widespread impact across affected systems. Organizations using Redis should assess their exposure and prioritize updates to safeguard against this vulnerability. Given the potential blast radius, it is critical for organizations to enact remediation measures quickly.
Exploitation Status
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. Additionally, various distributions such as Fedora (versions 33, 34, and 35) and Debian (versions 10.0 and 11.0) also include vulnerable versions of Redis.
Mitigation & Remediation
To mitigate the risks associated with CVE-2021-32628, organizations should apply the latest patches and update to Redis versions 6.2.6, 6.0.16, or 5.0.14. In cases where immediate patching is not feasible, organizations should restrict unprivileged users from modifying the ziplist configuration parameters using ACLs. This can prevent exploitation of the vulnerability while a patch is being deployed.
Organizations should also consider engaging in penetration testing to assess their security posture and identify other potential vulnerabilities.
Detection Guidance
To detect potential exploitation of CVE-2021-32628, organizations should monitor logs for unusual behavior related to the ziplist configurations. Additionally, behavioral anomalies in Redis operations, such as unexpected failures or high resource usage, should be investigated. Network signatures related to crafted commands targeting Redis should also be established to enhance detection capabilities.
AppSecure Threat Intelligence Insight
CVE-2021-32628 highlights the ongoing challenges associated with managing open-source software vulnerabilities. This incident represents a pattern of vulnerabilities that can arise from configuration parameters being mismanaged. Security teams should conduct thorough reviews of configuration settings across all software to mitigate similar vulnerabilities in the future. Furthermore, organizations should maintain an active vulnerability management program that prioritizes timely updates and assessments of their software landscape.
Developing a robust vulnerability management program can significantly reduce the risk of similar vulnerabilities going unnoticed and unaddressed.
Adopting effective penetration testing methodologies is essential for identifying and mitigating vulnerabilities before they can be exploited.
Furthermore, organizations should explore API penetration testing to ensure comprehensive security across their application ecosystems.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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