In lighttpd versions 1.4.46 through 1.4.63, the mod_extforward_Forwarded function of the mod_extforward plugin has a stack-based buffer overflow (4 bytes representing -1), leading to a potential remote denial of service (daemon crash) under specific non-default configurations. The non-default configuration involves handling the Forwarded header in an unusual manner, increasing the vulnerability's likelihood of exploitation on 32-bit systems compared to 64-bit systems. With a CVSS score of 5.9, this vulnerability is classified as medium severity, which may significantly impact system availability.
Risk to organizations includes potential service interruptions due to remote denial of service attacks. It is critical for organizations using affected versions to address this vulnerability promptly. The urgency for defenders is high, as it poses a risk of service disruption in production environments.
Currently, there is no public exploit confirmed for this vulnerability, and it is not included in the Known Exploited Vulnerabilities (KEV) catalog. However, organizations should remain vigilant and prioritize patching this vulnerability to mitigate potential risks.
Organizations should prioritize patching immediately, as the exploitability of the vulnerability in specific configurations could lead to significant operational disruptions.
Vulnerability Details
The vulnerability allows for a stack-based buffer overflow due to improper handling of the Forwarded header in Lighttpd's mod_extforward plugin. The vulnerability is classified under CWE-787 (Out-of-bounds Write). Affected products include Lighttpd versions 1.4.46 to 1.4.63 and Debian Linux versions 10.0 and 11.0.
Technical Analysis
The root cause of this vulnerability lies in the stack-based buffer overflow within the mod_extforward_Forwarded function. The attack vector is network-based, requiring high attack complexity since it involves specific non-default configurations to exploit. No privileges are required to exploit this vulnerability, and user interaction is not necessary.
The availability impact is assessed as high, as successful exploitation could lead to system crashes, causing service disruptions.
Risk & Impact Analysis
Organizations using affected versions of Lighttpd and Debian Linux are at risk of experiencing service outages due to this vulnerability. The potential blast radius includes any service relying on the affected versions, making it critical for organizations to evaluate the risk to their operational environment. Given the medium severity score and the complexity of exploitation, organizations should assess their exposure and take action to mitigate this risk.
The urgency assessment indicates that this vulnerability should be addressed in the priority patch cycle due to its potential impact on availability.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The vulnerability affects Lighttpd versions from 1.4.46 to 1.4.63 and Debian Linux versions 10.0 and 11.0. Organizations should ensure they are running patched versions to mitigate the risk.
Mitigation & Remediation
Organizations should prioritize applying patches provided by the vendor as soon as possible. For those unable to apply updates immediately, a temporary workaround may involve disabling the mod_extforward plugin if it is not essential for operation. Additionally, configuration hardening and monitoring for unusual traffic patterns can help mitigate potential exploitation.
For additional guidance, organizations can refer to the penetration testing methodology to assess their security posture.
Detection Guidance
Organizations should monitor logs for indicators of exploitation attempts related to the mod_extforward plugin. Behavioral anomalies and unusual network traffic patterns should be investigated. Additionally, system changes that coincide with the timing of potential attacks should be closely monitored.
AppSecure Threat Intelligence Insight
The long-term significance of this vulnerability lies in its potential to disrupt services on widely used web servers like Lighttpd. Security teams should be aware of similar patterns involving buffer overflow vulnerabilities in critical software components.
Organizations are encouraged to incorporate lessons learned from this vulnerability into their security training and awareness programs, ensuring that staff understand the risks associated with misconfigured server components.
For further insights on mitigating such vulnerabilities, security teams can explore our guides on web application penetration testing and penetration testing best practices to enhance their security posture.
By understanding the potential impacts and adopting proactive security measures, organizations can better defend against similar vulnerabilities in the future.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
.webp)