Catastrophic Backtracking Vulnerability in Python Packages: CVE-2018-1061
Summary
ALPINE-CVE-2018-1061: python before versions 2.7.15, 3.4.9, 3.5.6rc1, 3.6.5rc1 and 3.7.0 is vulnerable to catastrophic backtracking in the difflib.IS_LINE_JUNK method. Affects python2 versions < 2.7.15-r0. Fixed in 2.7.15-r0. How to fix ↓
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Background
Python is a widely-used high-level programming language known for its readability and versatility. It supports multiple programming paradigms and is utilized in various applications, from web development to data analysis. The vulnerability identified as CVE-2018-1061 affects specific versions of Python 2 and Python 3, where a flaw in the difflib.IS_LINE_JUNK method can lead to catastrophic backtracking, making the software susceptible to denial of service attacks.
Vulnerability Detail
The vulnerability arises from a flaw in the difflib.IS_LINE_JUNK method present in Python versions prior to 2.7.15, 3.4.9, 3.5.6rc1, 3.6.5rc1, and 3.7.0. This flaw allows an attacker to exploit the method, potentially causing a denial of service by consuming excessive resources. The technical aspect of this vulnerability lies in the way the method processes input, leading to performance degradation under certain conditions.
How To Fix
Minimum fixed version
2.7.15-r0
This is the first release that contains the fix.
sudo apk add --upgrade python2Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, users can limit the input size or sanitize the input to the difflib.IS_LINE_JUNK method to mitigate the risk of denial of service attacks until the package is updated.
Conclusion
CVE-2018-1061 represents a significant vulnerability in Python that can lead to denial of service attacks. Users are strongly encouraged to update their Python packages to the latest patched versions to mitigate this risk. Additionally, employing workarounds can provide temporary relief until updates are applied.
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FAQ
CVE-2018-1061 is a vulnerability in Python that allows for catastrophic backtracking in the difflib.IS_LINE_JUNK method, potentially leading to denial of service.
The vulnerability affects Python versions prior to 2.7.15, 3.4.9, 3.5.6rc1, 3.6.5rc1, and 3.7.0.
You can use Vulert's playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
The CVSS score of CVE-2018-1061 is 7.5, indicating a high severity level.
If immediate updates are not possible, consider implementing input size limitations or sanitization as a temporary workaround.
References
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