CVE-2013-3373 in Best Practical
Summary
by MITRE
CRLF injection vulnerability in Request Tracker (RT) 3.8.x before 3.8.17 and 4.0.x before 4.0.13 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via a MIME header.
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Analysis
by VulDB Data Team • 01/07/2022
The CVE-2013-3373 vulnerability represents a critical CRLF injection flaw in the Request Tracker (RT) software suite, specifically affecting versions 3.8.x prior to 3.8.17 and 4.0.x prior to 4.0.13. This vulnerability falls under the CWE-113 category, which specifically addresses improper neutralization of CRLF characters within HTTP headers, making it a direct descendant of the well-known HTTP response splitting attack vector. The flaw enables remote attackers to manipulate the application's HTTP response handling by injecting carriage return line feed sequences into MIME headers, thereby compromising the integrity of HTTP communications.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within RT's MIME header processing mechanisms. When the application processes user-supplied data that contains CRLF sequences within header fields, it fails to properly escape or filter these characters before incorporating them into HTTP responses. This allows attackers to inject additional HTTP headers or manipulate existing response headers, creating a pathway for various malicious activities including session hijacking, cross-site scripting attacks, and cache poisoning. The vulnerability specifically targets the application's handling of MIME headers, which are fundamental components of HTTP communication protocols and email message formatting within the RT system.
The operational impact of CVE-2013-3373 extends beyond simple header injection, as it enables sophisticated HTTP response splitting attacks that can completely compromise web application security. Attackers can leverage this vulnerability to inject malicious headers that redirect users to phishing sites, manipulate browser behavior through cache poisoning, or establish persistent sessions that bypass authentication mechanisms. The vulnerability's remote nature means that attackers do not require local access or privileged credentials to exploit it, making it particularly dangerous in multi-tenant environments where RT systems might be exposed to untrusted user inputs. This weakness directly maps to ATT&CK technique T1190, which describes the use of HTTP response splitting for web application attacks.
Organizations utilizing affected versions of Request Tracker face significant security risks including potential data breaches, unauthorized access to sensitive tickets and user information, and complete compromise of the application's security posture. The vulnerability can be exploited through various attack vectors including email submissions, web forms, and API endpoints that process user-supplied headers. Mitigation strategies should include immediate patching to versions 3.8.17 or 4.0.13, which contain proper input sanitization measures. Additional defensive measures include implementing strict header validation at the application level, deploying web application firewalls to detect and block CRLF sequences in HTTP headers, and establishing monitoring for anomalous header injection patterns. The vulnerability highlights the critical importance of proper input validation and output encoding in web applications, particularly those handling user-generated content in HTTP header contexts, and serves as a reminder of the persistent threat posed by insufficient sanitization of user inputs in security-critical systems.