Regular Expression Denial of Service (ReDoS) Vulnerability in ConfigObj Package
Summary
DEBIAN-CVE-2023-26112: All versions of the package configobj are vulnerable to Regular Expression Denial of Service (ReDoS) via the validate function, using (.+?)\((.*)\). Affects configobj versions < 5.0.8-2. Fixed in 5.0.8-2. How to fix ↓
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Background
ConfigObj is a Python library used for reading and writing complex configuration files. It allows developers to manage configurations in a structured manner, supporting nested data structures and various data types. However, all versions of ConfigObj are vulnerable to a Regular Expression Denial of Service (ReDoS) attack, which can occur when the validate function processes certain inputs.
Vulnerability Detail
The vulnerability arises from the use of a regular expression in the validate function: (.+?)((.*)). This regex can lead to catastrophic backtracking when processing specially crafted input, causing the application to hang or crash. This issue is particularly concerning for developers who may inadvertently include malicious input in server-side configuration files, potentially leading to service downtime or denial of service.
How To Fix
Minimum fixed version
5.0.8-2
This is the first release that contains the fix.
sudo apt-get install --only-upgrade configobjTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, developers should validate and sanitize any user inputs before they are processed by the validate function to prevent potential ReDoS attacks. Additionally, avoid using complex regular expressions that can lead to performance issues.
Conclusion
The ConfigObj package is vulnerable to a Regular Expression Denial of Service attack, which can severely impact application performance. It is crucial for developers to update to the patched version 5.0.8-2 or later and to implement input validation as a temporary measure. Utilizing tools like Vulert can help monitor and identify vulnerabilities in your applications.
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FAQ
ReDoS is a type of denial-of-service attack that exploits the inefficiencies of certain regular expressions, causing applications to consume excessive CPU resources and potentially crash.
You can check if your application is affected by this vulnerability using Vulert, which monitors open-source vulnerabilities in your software. Visit Vulert Scanner to analyze your manifest file.
If exploited, this vulnerability can lead to service downtime, degraded performance, and denial of service, impacting the availability of applications that rely on the ConfigObj package.
Yes, you can mitigate the risk by validating and sanitizing inputs before they reach the validate function, and by avoiding complex regex patterns.
If an immediate update is not possible, implement input validation and consider using alternative libraries that do not have this vulnerability.
References
Related vulnerabilities
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