Critical XXE Vulnerability in ModSecurity-Apache: Remote File Access and Denial of Service Risk
Summary
DEBIAN-CVE-2013-1915: ModSecurity before 2.7.3 allows remote attackers to read arbitrary files, send HTTP requests to intranet servers, or cause a denial of service (CPU and memory consumption) via an XML external entity declaration in conjun... Affects modsecurity-apache versions < 2.6.6-6. Fixed in 2.6.6-6. How to fix ↓
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Background
ModSecurity is an open-source web application firewall (WAF) designed to protect web applications from various attacks, including SQL injection, cross-site scripting (XSS), and more. It operates as an Apache module, providing real-time monitoring and logging of HTTP traffic. The vulnerability in question affects versions prior to 2.7.3, which are susceptible to XML External Entity (XXE) attacks, allowing unauthorized access to sensitive files and potential denial of service through resource exhaustion.
Vulnerability Detail
The vulnerability, identified as CVE-2013-1915, arises from ModSecurity's handling of XML external entity declarations. Attackers can exploit this flaw to read arbitrary files on the server, send HTTP requests to internal intranet servers, or cause denial of service by consuming excessive CPU and memory resources. This vulnerability poses significant risks, especially in environments where sensitive data is handled or where internal services are exposed.
How To Fix
Minimum fixed version
2.6.6-6
This is the first release that contains the fix.
sudo apt-get install --only-upgrade modsecurity-apacheTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, you can disable XML parsing in ModSecurity configurations to mitigate the risk of XXE attacks. This can be done by adding the following directive to your ModSecurity configuration file:
SecXMLExternalEntity 0
However, this is not a permanent solution and updating the package is strongly recommended.
Conclusion
The CVE-2013-1915 vulnerability in ModSecurity poses significant risks to web applications by allowing unauthorized file access and potential denial of service. It is crucial for users to update to the patched version 2.6.6-6 or later to mitigate these risks. Additionally, utilizing tools like Vulert can help in monitoring and managing open-source vulnerabilities effectively.
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FAQ
CVE-2013-1915 is a vulnerability in ModSecurity that allows remote attackers to exploit XML external entity declarations, leading to unauthorized file access and denial of service.
You can check your ModSecurity version by running 'modsecurity -v' in your terminal. If it is below 2.6.6-6, it is vulnerable.
The impacts include unauthorized access to sensitive files, potential exposure of internal services, and denial of service due to resource exhaustion.
Yes, Vulert can monitor and alert in real-time for open-source vulnerabilities using just a manifest file like package-lock.json.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
References
Related vulnerabilities
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