CVE-2023-23934 is a low-severity vulnerability found in Werkzeug, a comprehensive web application library. This vulnerability allows browsers to handle "nameless" cookies incorrectly, enabling a compromised application on an adjacent subdomain to set bad cookies for another subdomain. Specifically, prior to version 2.2.3, Werkzeug would parse cookies formatted as `=__Host-test=bad` incorrectly, recognizing them as valid keys. If a Werkzeug application is running alongside a malicious subdomain that sets such cookies, it may erroneously process the bad cookie value, leading to potential security issues.
The vulnerability's CVSS score is 2.6, categorizing it as low severity. The attack vector is classified as adjacent network, indicating that an attacker would need to be on the same network segment as the victim to exploit this vulnerability. The attack complexity is high, requiring user interaction, which limits the potential for widespread exploitation. However, organizations should be aware of the implications of this vulnerability, especially if they operate applications that may be exposed to adjacent subdomains.
Risk to organizations includes the potential for unauthorized cookie values being accepted by the application, which could lead to integrity issues. Although the integrity impact is classified as low, and there are no confidentiality or availability impacts, the vulnerability could still be leveraged in specific attack scenarios. Organizations utilizing Werkzeug should ensure they update to version 2.2.3 or later to mitigate this risk.
Given the current status of this vulnerability, organizations should schedule remediation during their priority patch cycle to prevent any potential exploitation through adjacent subdomains.
Vulnerability Details
The official CVE description states: "Werkzeug is a comprehensive WSGI web application library. Browsers may allow 'nameless' cookies that look like `=value` instead of `key=value`. A vulnerable browser may allow a compromised application on an adjacent subdomain to exploit this to set a cookie like '=__Host-test=bad' for another subdomain. Werkzeug prior to 2.2.3 will parse the cookie '=__Host-test=bad' as __Host-test=bad'."
This vulnerability has a CVSS score of 2.6, which indicates low severity. The affected product is Werkzeug, developed by Palletsprojects, and the issue was published on February 14, 2023, with modifications noted until November 21, 2024.
This vulnerability is classified under CWE-20, which indicates improper input validation. Organizations should ensure that they are running versions of Werkzeug that are 2.2.3 or higher to mitigate this risk.
Technical Analysis
The root cause of CVE-2023-23934 lies in the way Werkzeug processes cookies that are set without a key. Browsers that allow nameless cookies can result in unexpected behavior when the application is not properly validating cookie input. As such, this vulnerability poses a significant risk when adjacent subdomains are involved.
The attack vector is classified as adjacent network, meaning that an attacker would need to be on the same local network segment as the target. The attack complexity is considered high, requiring user interaction to exploit. No privileges are required to exploit this vulnerability, and user interaction is necessary for the attack to succeed.
The confidentiality impact is none, while the integrity impact is low, as the attacker may alter cookie values without a valid key. There is no impact on availability.
Risk & Impact Analysis
Organizations running vulnerable versions of Werkzeug could face risks related to cookie integrity. Attackers may exploit this vulnerability to set bad cookies, leading to incorrect application behavior or potential unauthorized actions. The blast radius is limited due to the high attack complexity and the requirement for user interaction, but the risk remains significant in environments where adjacent subdomains are in use.
Organizations should monitor their environments for any indications of this vulnerability being exploited and prioritize patching as part of their security maintenance routine. Given the low CVSS score, organizations may address this issue in their routine maintenance cycle, but timely remediation is still recommended to avoid potential exploitation.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
All versions of Werkzeug prior to 2.2.3 are affected by this vulnerability. Organizations should ensure they upgrade to the latest version to mitigate any risks associated with this vulnerability.
Mitigation & Remediation
To mitigate this vulnerability, organizations should immediately upgrade to Werkzeug version 2.2.3 or later. If upgrading is not possible, consider implementing workarounds such as configuring proper cookie handling and validating cookie inputs to prevent exploitation. Additionally, organizations should conduct regular security assessments and consider engaging in penetration testing to evaluate the effectiveness of their security controls.
Detection Guidance
Organizations should monitor application logs for any anomalies related to cookie values. Behavioral indicators such as unexpected cookie values or unauthorized access attempts may also signal attempts to exploit this vulnerability. Implementing network monitoring can help detect any suspicious traffic related to cookie manipulation.
AppSecure Threat Intelligence Insight
The significance of CVE-2023-23934 lies in its representation of a common issue in web application security where improper cookie handling can lead to integrity problems. Organizations should take this as a reminder to audit cookie management policies and ensure that cookie values are validated appropriately.
As organizations continue to evolve their security postures, understanding vulnerabilities like this is crucial. Regular engagement with security professionals and continuous improvement of security practices can help mitigate risks associated with such vulnerabilities. For further reading on vulnerability management, consider our vulnerability management program and best practices for secure application development.
Additionally, organizations should explore our resources on penetration testing methodologies to enhance their security frameworks.
Understanding the implications of vulnerabilities like CVE-2023-23934 is essential for maintaining a robust security posture. Organizations should stay informed about developments in application security to proactively protect their assets.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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