CVE-2024-3220 is a low-severity vulnerability affecting the CPython standard library. This defect arises from the default list of known file locations in the mimetypes module being writable on Windows. As a result, other users can create invalid files, potentially causing a MemoryError when the Python runtime starts, or misinterpreting file extensions.
The issue is rooted in the design choice to use default locations that also exist on Linux and macOS, such as '/etc/mime.types', which are user-writable on Windows as 'C:\etc\mime.types'. This inconsistency leads to potential runtime errors and incorrect file type handling.
To mitigate this risk, users are advised to invoke mimetypes.init() with an empty list ('[]') on Windows platforms. This workaround prevents the use of the default file locations that can be compromised.
Given the low CVSS score of 2.3, the risk to organizations includes potential disruptions during Python runtime initialization. However, organizations should still prioritize addressing this vulnerability as part of their security practices.
While there are known exploits available, the overall exploitability is considered low. Organizations should remain vigilant and implement the recommended workaround to minimize risks associated with this vulnerability.
Vulnerability Details
CVE-2024-3220 is classified under CWE-426, which pertains to 'The default list of known file locations in the CPython standard library module 'mimetypes' is writable on Windows.' The CVSS score of 2.3 indicates a low severity level, primarily due to the attack complexity being low and the requirement for user interaction being absent.
This vulnerability was published on February 14, 2025, and affects the CPython standard library. Organizations utilizing this library in their applications should assess their exposure and implement necessary remediation.
Technical Analysis
The root cause of CVE-2024-3220 lies in the writable nature of the default mime types file locations on Windows systems. Specifically, when Python is executed, it reads these locations to determine file types. If malicious users create invalid mime type files, it can lead to a MemoryError, disrupting the initialization process of the Python runtime.
The attack vector for this vulnerability is classified as NETWORK, meaning the attack could originate from any networked device. The attack complexity is deemed low, with low privileges required for exploitation, and no user interaction is necessary for the attack to be successful.
The impacts of a successful exploit include low integrity and availability impacts, as the primary outcome is a MemoryError during the runtime startup, which can cause applications to crash or misbehave.
Risk & Impact Analysis
The real-world risk associated with CVE-2024-3220 is relatively low, given its low severity rating and exploitability. However, organizations that rely on Python for critical applications should assess the potential blast radius if exploited, particularly in environments where multiple users have access to the writable mime types locations.
Organizations should prioritize patching this vulnerability in their upcoming patch cycles and consider implementing the workaround to mitigate risks associated with invalid file types being loaded at runtime.
The urgency for organizations is moderate, and while immediate action may not be required, a proactive approach is recommended to prevent disruptions in the Python runtime environment.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | Yes |
Public PoC | Yes |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
Currently, there are no specific affected versions listed. Organizations using the CPython standard library should consider all versions prior to the vendor patch as potentially vulnerable.
Mitigation & Remediation
To remediate CVE-2024-3220, organizations should apply the following steps:
1. Call `mimetypes.init()` with an empty list (`[]`) on Windows platforms to avoid using default locations.
2. Monitor for any updates from the CPython project regarding patches or fixes.
3. Implement appropriate access controls to restrict write access to the mentioned file locations.
For further insights on effective security practices, consider reviewing our guide on application security assessment.
Detection Guidance
To effectively monitor for exploitation of this vulnerability, organizations should look for the following indicators:
1. Logs indicating attempts to create or modify files in the writable mime types locations.
2. Behavioral anomalies in Python applications that may point to unusual file type handling.
3. Network signatures that correspond with the usage of the mimetypes module.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2024-3220 lies in its demonstration of how misconfigurations in standard libraries can lead to exploitable vulnerabilities. Security teams should take this as a reminder to regularly audit their application's dependencies and libraries for similar risks.
This vulnerability also highlights the importance of rigorous security practices when developing libraries, ensuring that file handling mechanisms are secure by default. Organizations should review their security posture and consider implementing strategies such as penetration testing methodology to identify similar weaknesses in their applications.
Proactive engagement with security assessments will allow organizations to better safeguard their systems against future vulnerabilities, reinforcing their overall security posture.
Finally, organizations should remain aware of evolving threats and trends in the security landscape, leveraging resources such as our vulnerability management program to stay ahead of potential risks.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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