CVE-2021-36160 is a high-severity vulnerability affecting Apache HTTP Server versions 2.4.30 to 2.4.48. This vulnerability allows a carefully crafted request uri-path to cause mod_proxy_uwsgi to read above the allocated memory, resulting in a Denial of Service (DoS). The impact is critical, as it can lead to service disruptions and unavailability.
With a CVSS score of 7.5, this vulnerability poses a significant risk to organizations using the affected versions of Apache. The attack vector is network-based with low complexity, requiring no privileges or user interaction from the attacker. Given these factors, the urgency for defenders is high, and organizations should prioritize patching immediately.
As of now, there are no known exploits in the wild, and no public proof-of-concept (PoC) has been confirmed. However, the nature of the vulnerability and its potential impact necessitate proactive measures to secure systems against possible exploitation.
Organizations using the affected versions should not only apply the necessary patches but also review logging and monitoring processes to detect any unusual activity related to this vulnerability.
Vulnerability Details
The official description of this vulnerability states that a crafted request uri-path can cause mod_proxy_uwsgi to read above the allocated memory, leading to a crash (Denial of Service). The CWE classification for this vulnerability is CWE-125, which corresponds to Out-of-Bounds Read.
The CVSS score for this vulnerability is 7.5, classifying it as high severity. The attack is executed over the network with low complexity, requiring no privileges or user interaction. Its impact is primarily on availability, leading to potential service interruptions.
Technical Analysis
The root cause of this vulnerability lies in the handling of user-supplied data by mod_proxy_uwsgi. Attackers may send specially crafted requests that cause the server to read outside its allocated memory space, which can lead to application crashes. The attack vector is network-based, allowing remote attackers to exploit this vulnerability without needing physical access to the server.
Given that the attack complexity is low, an attacker does not need elevated privileges or extensive knowledge of the system to exploit this vulnerability. There is no requirement for user interaction, making it easier for attackers to execute the attack successfully.
The impact on availability is critical, as the vulnerability allows for repeated crashes of the service, which can disrupt normal operations. Organizations using Apache HTTP Server should be aware of this potential impact and take immediate action to patch the vulnerability.
Risk & Impact Analysis
Organizations using vulnerable versions of Apache HTTP Server face significant operational risks due to this vulnerability. The potential for Denial of Service attacks means that attackers could exploit this vulnerability to disrupt services, leading to downtime and loss of business continuity.
The blast radius for this vulnerability could be extensive, particularly for organizations with a large number of exposed Apache servers. This risk is exacerbated by the fact that the attack is network-based, enabling attackers to target systems remotely without needing physical access.
Given the CVSS score of 7.5, organizations should assess their patching priorities to address this vulnerability in their next patch cycle. The urgency for remediation is high, especially considering the potential for exploitation in the wild.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The vulnerability affects Apache HTTP Server versions 2.4.30 to 2.4.48 (inclusive). Organizations should ensure that they update to the latest versions to mitigate this risk.
Mitigation & Remediation
To remediate this vulnerability, organizations should upgrade to Apache HTTP Server version 2.4.49 or later. Patching should be prioritized due to the high severity of this vulnerability. If immediate patching is not possible, consider implementing temporary workarounds such as restricting access to mod_proxy_uwsgi and reviewing server configurations.
Organizations can also benefit from ongoing security assessments and reviews. Regular security testing can help identify potential vulnerabilities before they can be exploited. For more information on effective security testing, organizations may consider engaging in penetration testing to assess their security posture.
Detection Guidance
Organizations should monitor logs for unusual patterns, particularly requests targeting mod_proxy_uwsgi. Indicators of compromise may include repeated crashes or service interruptions. Implementing robust logging and alerting mechanisms can help detect potential exploitation attempts.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-36160 underscores the importance of robust coding practices and thorough testing before deployment. This vulnerability serves as a reminder of the risks associated with improper memory handling, which can lead to significant service disruptions.
Security teams should take this opportunity to review their development processes and ensure that similar vulnerabilities are mitigated in the future. Patterns of vulnerabilities like this can indicate a need for improved security training for developers.
For organizations looking to enhance their security posture, engaging in services such as application security assessments and implementing a comprehensive red teaming service can help identify and remediate vulnerabilities proactively.
To summarize, the immediate response to this vulnerability should include patching, enhanced monitoring, and a review of security practices to prevent similar incidents in the future.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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