CVE-2013-6009 in AppSuite
Summary
by MITRE
CRLF injection vulnerability in Open-Xchange AppSuite before 7.2.2, when using AJP in certain conditions, allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via the ajax/defer servlet.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 03/01/2019
The CVE-2013-6009 vulnerability represents a critical CRLF injection flaw in Open-Xchange AppSuite versions prior to 7.2.2 that specifically manifests when the application employs AJP protocol connections. This vulnerability resides within the ajax/defer servlet component and enables remote attackers to manipulate HTTP headers through carefully crafted input sequences. The flaw stems from inadequate input validation and sanitization of user-supplied data that flows into HTTP response headers, creating a pathway for malicious actors to inject carriage return line feed sequences that disrupt normal HTTP communication patterns.
The technical implementation of this vulnerability exploits the fundamental weakness in how the application processes user input when operating through AJP connections. When a user submits data to the ajax/defer servlet, the application fails to properly sanitize this input before incorporating it into HTTP response headers. This allows attackers to insert CRLF sequences that can terminate existing headers and inject new malicious headers into the HTTP response. The attack vector specifically leverages the AJP protocol's handling of HTTP headers, where the vulnerability becomes exploitable due to the application's insufficient validation of input data that eventually gets rendered in HTTP responses. The vulnerability can be classified under CWE-113, which specifically addresses improper neutralization of CRLF characters in HTTP headers, and aligns with ATT&CK technique T1071.004 for application layer protocol manipulation.
The operational impact of this vulnerability extends beyond simple header injection, as it enables full HTTP response splitting attacks that can be leveraged for various malicious activities including session hijacking, cross-site scripting, and cache poisoning. Attackers can manipulate the HTTP response to inject additional headers that redirect users to malicious sites, inject malicious content into web pages, or manipulate browser behavior through crafted response headers. The vulnerability is particularly dangerous because it operates at the application layer and can be exploited without requiring authentication, making it an attractive target for automated attacks. The AJP protocol context adds complexity to the exploitation process, as it requires specific environmental conditions to be present for the vulnerability to manifest properly.
Mitigation strategies for CVE-2013-6009 should focus on immediate patch deployment to update Open-Xchange AppSuite to version 7.2.2 or later, which contains the necessary fixes for input validation and header sanitization. Organizations should implement comprehensive input validation at all entry points, particularly for data that will be incorporated into HTTP headers, and deploy web application firewalls that can detect and block CRLF injection attempts. Network segmentation and access controls should be implemented to limit exposure, while regular security assessments should verify that all components are properly updated. The fix addresses the root cause by implementing proper input sanitization and validation mechanisms that prevent CRLF sequences from being processed in HTTP header contexts, effectively closing the attack vector that allows for HTTP response splitting and header injection attacks. Additionally, security monitoring should be enhanced to detect unusual header patterns that might indicate exploitation attempts.