In PHP versions before 7.4.31, 8.0.24, and 8.1.11, the phar uncompressor code would recursively uncompress "quines" gzip files, resulting in an infinite loop. This vulnerability allows attackers to exploit the uncompression process, leading to a denial of service condition.
The CVSS score for this vulnerability is 2.3, classified as low severity. Despite its low score, the potential for an infinite loop poses a risk to service availability, particularly for systems relying heavily on PHP scripts for processing.
As this vulnerability has been classified with a low CVSS score, organizations might consider it less urgent. However, risk to organizations includes the potential for denial of service attacks that could disrupt services. Organizations should prioritize patching immediately.
Currently, there are no known exploits or public proofs of concept for this vulnerability, indicating a lower immediate threat but still requiring attention to prevent possible future exploitation.
Vulnerability Details
The vulnerability affects PHP versions prior to 7.4.31, 8.0.24, and 8.1.11. The specific issue arises from the handling of "quines" gzip files, which leads to infinite loops during the uncompression process. This vulnerability is classified under CWE-674 (Uncontrolled Recursion) and CWE-835 (Infinite Loop).
The primary source for this vulnerability is from the PHP security team, with an identification date of September 28, 2022. The affected products include various distributions of PHP, as well as Debian and Fedora operating systems.
Technical Analysis
The root cause of this vulnerability lies in the implementation of the phar uncompressor code. The uncompressor is designed to handle gzip files, but it fails to adequately check for recursive conditions when processing "quines" gzip files. As a result, an attacker can create a specially crafted gzip file that triggers this recursion, leading to an infinite loop.
The attack vector for this vulnerability is local, meaning an attacker must have access to the system where PHP is running. The attack complexity is low, as no special requirements are needed beyond having the ability to execute PHP scripts. Privileges required are high, indicating that an attacker would need specific access rights to exploit the vulnerability.
User interaction is not required for this vulnerability to be exploited. The impacts include low availability, as the infinite loop can consume system resources, potentially leading to a denial of service scenario.
Risk & Impact Analysis
The real-world risk associated with this vulnerability is primarily around availability. Systems running affected PHP versions may become unresponsive if exploited. The potential blast radius for organizations includes any services utilizing these versions of PHP, particularly in web applications and APIs.
Given the low CVSS score and the absence of known exploits, organizations may deprioritize immediate action. However, organizations should address this vulnerability in their patch cycle to mitigate the risk of potential denial-of-service attacks.
Organizations should schedule remediation to ensure that they are protected against this vulnerability. While the urgency is low, it is critical to maintain an up-to-date security posture.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
Affected versions of PHP include all versions prior to 7.4.31, 8.0.24, and 8.1.11. Debian Linux versions 10.0 and 11.0, as well as Fedora versions 35, 36, and 37 are also impacted.
Mitigation & Remediation
Organizations should ensure they upgrade their PHP installations to versions 7.4.31, 8.0.24, or 8.1.11 to mitigate this vulnerability. If a patch is unavailable, consider implementing configuration hardening to limit the impact of the vulnerability.
Monitoring for unusual resource consumption patterns may help detect potential exploitation attempts. Additionally, consider network controls to limit access to systems running vulnerable versions of PHP.
For organizations looking to validate their security posture, engaging in regular penetration testing can be beneficial.
Detection Guidance
Monitoring system logs for anomalies related to PHP execution can help identify potential exploitation attempts. Look for patterns of excessive resource consumption or repeated uncompression actions. Additionally, network signatures indicating unusual traffic patterns to PHP applications may signal attempts to exploit this vulnerability.
AppSecure Threat Intelligence Insight
The long-term significance of this vulnerability lies in its demonstration of how even low-severity issues can lead to impactful service disruptions if left unaddressed. It highlights the importance of maintaining updated software and being vigilant about vulnerabilities.
As organizations increasingly rely on PHP for web applications, the need for continuous security assessments becomes evident. Teams should learn from this vulnerability to ensure proactive defense strategies.
A strategic takeaway for security teams is to incorporate vulnerability management practices into their development cycles. Regular updates and security testing, such as vulnerability management programs, can help mitigate risks associated with outdated software.
Security teams should also consider adopting a comprehensive penetration testing methodology to identify similar weaknesses in their environment.
Furthermore, integrating security practices into the software development lifecycle ensures that vulnerabilities are addressed at the earliest stages of development.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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