CVE-2021-28831 is a high-severity vulnerability found in BusyBox, specifically in the decompress_gunzip.c file. This vulnerability allows mishandling of the error bit in the huft_build result pointer, leading to an invalid free or segmentation fault when processing malformed gzip data. The vulnerability affects versions of BusyBox up to 1.32.1.
The Common Vulnerability Scoring System (CVSS) score for this vulnerability is 7.5, indicating high severity. With an attack vector of NETWORK and low complexity, this vulnerability can be exploited without requiring any privileges or user interaction. Organizations running affected versions of BusyBox should be particularly aware of the risks this vulnerability poses.
Risk to organizations includes potential denial of service due to the vulnerability's impact on availability. This risk is exacerbated since the vulnerability can be triggered remotely without authentication. Organizations that rely on BusyBox for critical services should prioritize patching this vulnerability immediately.
Currently, there are no known exploits in the wild, but the nature of the vulnerability suggests it could be a target for attackers. Therefore, immediate attention and remediation are advised.
Vulnerability Details
The vulnerability is classified as CWE-755, indicating improper handling of exceptional conditions. It was published on March 19, 2021, and is classified as Modified due to updates in its status.
Affected systems include BusyBox versions up to 1.32.1, as well as various distributions that utilize BusyBox, such as Fedora and Debian.
The availability impact is rated as HIGH, while confidentiality and integrity impacts are rated as NONE, emphasizing the primary concern is service availability.
Technical Analysis
The root cause of CVE-2021-28831 lies in the mishandling of the huft_build result pointer in the decompress_gunzip.c code. When malformed gzip data is processed, the error bit is not handled correctly, leading to potential invalid memory access.
The attack vector is NETWORK, meaning that an attacker can exploit this vulnerability remotely. The complexity of the attack is low, as no special conditions are required for exploitation, and no privileges are needed to trigger the vulnerability.
There is no requirement for user interaction, which further simplifies the exploitation process. The vulnerability’s availability impact is categorized as HIGH, suggesting that successful exploitation could lead to service interruption.
Risk & Impact Analysis
The risk to organizations includes service disruption due to denial of service attacks. Given the widespread use of BusyBox in various embedded systems and Linux distributions, the potential blast radius is significant.
Organizations should assess their exposure to this vulnerability based on their use of BusyBox in critical systems. The urgency for patching is high, especially for systems exposed to the internet or untrusted networks.
Given the CVSS score of 7.5 and the absence of a known exploit, organizations must still take this vulnerability seriously. Immediate action is recommended in the patch cycle to mitigate risks associated with this vulnerability.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions include BusyBox versions from 1.32.0 to 1.32.1. Other affected products include Fedora versions 32, 33, and 34, and Debian Linux version 9.0.
Mitigation & Remediation
Organizations should prioritize patching BusyBox to the latest version that addresses the vulnerability. If a patch is unavailable, consider implementing workarounds such as restricting access to affected systems or utilizing alternative software.
Configuration hardening can also reduce exposure. Implementing strict network controls and monitoring can help detect attempts to exploit this vulnerability before they result in damage.
For further assistance in assessing your security posture, organizations can consider engaging in penetration testing services.
Detection Guidance
To detect potential exploitation of CVE-2021-28831, organizations should monitor logs for unexpected crashes or segmentation faults related to BusyBox. Behavioral anomalies in service responsiveness may also indicate attempted exploitation.
Network signatures for malformed gzip data can be established to enhance detection capabilities.
AppSecure Threat Intelligence Insight
The significance of CVE-2021-28831 lies in its potential to lead to denial of service attacks, posing a substantial risk for organizations relying on BusyBox. This vulnerability showcases the importance of maintaining updated software and prompt patching practices.
Security teams should incorporate this case into their vulnerability management program to ensure ongoing assessment of software risks.
The trends in vulnerabilities such as this emphasize the ongoing need for proactive security measures. Regular reviews of software dependencies and timely patching can significantly reduce risk exposure.
Organizations can benefit from strategic initiatives including penetration testing methodology to identify and remediate similar vulnerabilities.
In conclusion, CVE-2021-28831 serves as a reminder to organizations about the critical importance of secure coding practices and the need for continuous monitoring of vulnerabilities.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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