CVE-2021-31525 is a medium-severity vulnerability affecting the net/http package in Go versions before 1.15.12 and 1.16.x before 1.16.4. This vulnerability allows remote attackers to cause a denial of service (panic) by sending a large header to the ReadRequest or ReadResponse functions. All components, including Server, Transport, and Client, can be impacted under certain configurations.
The CVSS v3.1 score for this vulnerability is 5.9, which indicates a medium level of severity. The availability impact is rated as high, meaning that successful exploitation can cause significant disruptions. Organizations using affected versions of Go should take this vulnerability seriously and implement necessary patches immediately.
Currently, there are no known public exploits for this vulnerability. However, attackers may leverage this issue to destabilize services, especially in high-traffic applications. Organizations should prioritize patching immediately to mitigate the risk of potential exploitation.
Given the potential for denial of service, it is critical to address this vulnerability in the next patch cycle. The urgency for remediation stems from the possibility of service outages and the impact on user experience.
Vulnerability Details
The official description of CVE-2021-31525 states that the net/http package in Go versions before 1.15.12 and 1.16.x before 1.16.4 allows remote attackers to cause a denial of service (panic) via a large header sent to ReadRequest or ReadResponse. The vulnerability affects multiple components, including Server, Transport, and Client, depending on the configuration.
The vulnerability is classified under CWE-674, which relates to expected behavior for the handling of large inputs. The CVSS score of 5.9 reflects a medium impact on availability, indicating a significant risk to application uptime.
The vulnerability was published on May 27, 2021, and has been modified since then. Organizations should review their usage of the Go programming language and ensure they are running versions that include the necessary patches.
Technical Analysis
The root cause of CVE-2021-31525 lies in how the Go net/http package handles large HTTP headers. When a large header is processed by the ReadRequest or ReadResponse functions, it can lead to a stack overflow, resulting in a panic state. This vulnerability can be exploited remotely over the network, making it a significant concern for applications exposed to external traffic.
The attack vector is network-based, requiring no authentication or user interaction. The attack complexity is rated as high, indicating that while exploitation is possible, it may require specific conditions to succeed. The availability impact is rated high, meaning successful exploitation can lead to service outages.
In the context of deployment, this vulnerability poses a risk to organizations running applications that handle HTTP requests with potentially large headers. Organizations should consider implementing input validation and monitoring to detect any anomalies or unusual patterns in traffic that could indicate exploitation attempts.
Risk & Impact Analysis
Risk to organizations includes potential service disruptions, which can affect customer experience and operational efficiency. The blast radius of this vulnerability can be significant if exploited, particularly in high-traffic environments. Organizations should be aware that denial of service attacks can lead to loss of revenue and customer trust.
Given the CVSS score of 5.9, organizations should address this vulnerability in their priority patch cycle. The risk of exploitation may be low due to the lack of known exploits, but the availability impact is high, warranting immediate attention.
Organizations should prioritize patching immediately. Implementing network controls and monitoring can help mitigate risks associated with this vulnerability while remediation efforts are underway.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The vulnerability affects all versions of Go prior to 1.15.12 and versions 1.16.x prior to 1.16.4. Organizations should ensure that they are using patched versions of Go to avoid this vulnerability.
Mitigation & Remediation
To mitigate the risk associated with CVE-2021-31525, organizations should upgrade to the latest stable version of Go that includes the necessary patches. For those unable to upgrade immediately, implementing input validation to limit header sizes and monitoring network traffic for anomalies can help reduce exposure.
Organizations are encouraged to review their application security posture and consider utilizing penetration testing to identify potential vulnerabilities before they can be exploited.
Detection Guidance
Organizations should monitor logs for signs of abnormal behavior, specifically focusing on any requests that contain unusually large headers. Behavioral anomalies in application responses should also be reviewed for indicators of attempted exploitation.
AppSecure Threat Intelligence Insight
CVE-2021-31525 highlights the ongoing need for organizations to maintain a proactive stance on application security. As vulnerabilities continue to evolve, it is crucial for security teams to regularly assess their environments and ensure that they are updated with the latest security patches. This incident serves as a reminder of the importance of penetration testing methodology and effective vulnerability management practices.
Furthermore, organizations should consider engaging in vulnerability management programs that emphasize continuous monitoring and assessment to stay ahead of potential threats.
Lastly, organizations should stay informed about emerging threats and trends, as well as best practices in application security through resources such as the API penetration testing guide and other relevant literature.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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