CVE-2015-0733 in Headend System Release
Summary
by MITRE
CRLF injection vulnerability in the HTTP Header Handler in Digital Broadband Delivery System in Cisco Headend System Release allows remote attackers to inject arbitrary HTTP headers, and conduct HTTP response splitting attacks or cross-site scripting (XSS) attacks, via a crafted request, aka Bug ID CSCur25580.
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Analysis
by VulDB Data Team • 05/19/2022
The CVE-2015-0733 vulnerability represents a critical CRLF injection flaw within the HTTP header handling component of Cisco's Headend System Release, specifically affecting the Digital Broadband Delivery System. This vulnerability resides in the HTTP header handler functionality that processes incoming requests from remote attackers, creating a pathway for malicious input manipulation. The flaw stems from inadequate input validation and sanitization of user-supplied data within HTTP header processing routines, allowing attackers to inject carriage return line feed sequences that can alter the behavior of HTTP responses.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious HTTP request containing CRLF sequences within header values or parameters. These sequences, typically represented as %0d%0a or \r\n in URL encoding, can be injected into vulnerable applications that do not properly validate or escape user input. When processed by the affected Cisco system, these injected sequences enable attackers to manipulate HTTP headers, effectively splitting responses or injecting malicious content into the HTTP stream. This vulnerability directly maps to CWE-113, which describes improper neutralization of CRLF sequences in HTTP headers, and aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as attackers can leverage this to inject malicious scripts into HTTP responses.
The operational impact of this vulnerability is severe, as it enables multiple attack vectors including HTTP response splitting, which allows attackers to inject multiple HTTP responses into a single HTTP transaction, potentially leading to cache poisoning or session hijacking. Additionally, the vulnerability can be exploited to conduct cross-site scripting attacks by injecting malicious JavaScript code into HTTP headers, which can then be executed in the victim's browser when the manipulated headers are processed. This creates a persistent threat that can compromise user sessions, steal sensitive information, or redirect users to malicious websites. The vulnerability affects Cisco's Headend System Release, which typically serves as a critical component in digital broadcasting and content delivery infrastructure, making the potential impact substantial for organizations relying on this technology.
Mitigation strategies for CVE-2015-0733 should include immediate implementation of input validation and sanitization measures that properly escape or filter CRLF sequences from all user-supplied input before processing. Organizations should deploy web application firewalls that can detect and block CRLF injection attempts, and ensure that all HTTP headers are properly validated against known safe character sets. Cisco released patches addressing this vulnerability in subsequent releases, and system administrators should implement these updates immediately. Network segmentation and monitoring solutions should be employed to detect anomalous HTTP header patterns that may indicate exploitation attempts. The vulnerability also highlights the importance of secure coding practices, particularly in handling user input within HTTP processing components, and demonstrates the necessity of regular security assessments and penetration testing to identify similar injection vulnerabilities in network infrastructure components.