CVE-2003-1338 in Abyss Web Server
Summary
by MITRE
CRLF injection vulnerability in Aprelium Abyss Web Server 1.1.2 and earlier allows remote attackers to inject arbitrary HTTP headers and possibly conduct HTTP Response Splitting attacks via CRLF sequences in the Location header.
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Analysis
by VulDB Data Team • 07/04/2017
The CVE-2003-1338 vulnerability represents a critical CRLF (Carriage Return Line Feed) injection flaw discovered in the Aprelium Abyss Web Server version 1.1.2 and earlier releases. This vulnerability resides in the server's handling of HTTP headers, specifically within the Location header processing mechanism. The flaw allows remote attackers to inject malicious CRLF sequences that can manipulate the HTTP response structure, creating a pathway for various sophisticated attacks including HTTP response splitting. The vulnerability stems from insufficient input validation and sanitization of user-supplied data that gets incorporated into HTTP headers without proper encoding or filtering mechanisms.
The technical exploitation of this vulnerability occurs when an attacker provides malicious input containing CRLF sequences such as \r\n or %0d%0a in the Location header value. When the web server processes this input and includes it directly in the HTTP response without proper sanitization, the injected sequences can break the normal HTTP response format. This disruption allows attackers to inject additional HTTP headers or even entire HTTP responses, effectively enabling them to manipulate the web server's behavior and potentially redirect users to malicious sites or inject content into web pages. The vulnerability operates at the protocol level where HTTP responses are constructed, making it particularly dangerous as it can bypass many traditional security controls.
From an operational perspective, this vulnerability creates significant risks for web applications relying on the affected Abyss Web Server version. Attackers can leverage this flaw to conduct HTTP response splitting attacks, which can lead to session hijacking, cross-site scripting, cache poisoning, and man-in-the-middle attacks. The impact extends beyond simple header injection as the ability to manipulate HTTP responses can be combined with other techniques to create more complex attack vectors. The vulnerability affects the fundamental integrity of HTTP communications, potentially allowing attackers to modify or inject content that users perceive as legitimate from the web server. This makes it particularly dangerous in environments where user trust and data integrity are paramount.
Mitigation strategies for CVE-2003-1338 should focus on immediate remediation through software updates and patches provided by the vendor. Organizations should upgrade to versions of the Abyss Web Server that address this vulnerability, as the flaw is inherent in the server's code implementation rather than configuration settings. Additionally, implementing proper input validation and sanitization measures at the application level can provide defense-in-depth protection. This includes filtering or encoding user-supplied data before it is incorporated into HTTP headers, particularly the Location header. Network-level protections such as web application firewalls can also help detect and block malicious CRLF sequences in HTTP requests. The vulnerability aligns with CWE-117, which addresses improper output neutralization for logs, and maps to ATT&CK technique T1190 for exploiting vulnerabilities in web applications. Organizations should also implement monitoring and logging mechanisms to detect unusual HTTP response patterns that might indicate exploitation attempts, ensuring comprehensive protection against this and similar vulnerabilities.