CVE-2005-1087 in AN-HTTPd
Summary
by MITRE
CRLF injection vulnerability in the cmdIS.DLL plugin for AN HTTPD Server 1.42n allows remote attackers to spoof or hide entries in the logfile, and possibly read files using an injected type command, via CRLF sequences in an HTTP request.
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Analysis
by VulDB Data Team • 07/01/2021
The vulnerability identified as CVE-2005-1087 represents a critical CRLF injection flaw within the cmdIS.DLL plugin of AN HTTPD Server version 1.42n. This issue stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied data before processing HTTP requests. The vulnerability specifically affects the server's logging functionality and file access controls, creating potential security risks for systems running this particular web server software. The flaw enables malicious actors to manipulate the server's behavior through carefully crafted HTTP requests containing CRLF (Carriage Return Line Feed) sequences that are typically used to terminate lines in HTTP protocol communications.
The technical exploitation of this vulnerability occurs when an attacker crafts HTTP requests that include CRLF sequences in parameters processed by the cmdIS.DLL plugin. These sequences allow attackers to inject malicious commands that can manipulate the server's logging behavior, enabling them to spoof or hide log entries that would normally be recorded during legitimate server operations. The vulnerability operates at the protocol level where the server fails to properly validate and escape special characters, particularly those that define the boundaries of HTTP headers and request lines. This allows attackers to inject additional headers or commands that can bypass normal access controls and potentially execute unauthorized file operations.
The operational impact of this vulnerability extends beyond simple log manipulation, as it provides potential attackers with pathways to access sensitive server information and perform unauthorized operations. When an attacker successfully exploits this vulnerability, they can inject commands that may allow them to read files from the server filesystem that would normally be protected from direct access. The ability to manipulate log entries also creates opportunities for attackers to cover their tracks or obscure malicious activities from security monitoring systems. This vulnerability essentially undermines the integrity of the server's logging infrastructure and creates potential pathways for further exploitation through file access and command execution capabilities.
Security professionals should consider this vulnerability in the context of CWE-113, which specifically addresses improper neutralization of CRLF sequences in HTTP headers, and aligns with ATT&CK technique T1071.004 for application layer protocol manipulation. The vulnerability demonstrates the critical importance of input validation and proper sanitization of user-supplied data in web server applications, particularly those handling HTTP requests that may contain special characters. Organizations running affected versions of AN HTTPD Server should immediately implement mitigations including patching to the latest stable version, implementing proper input validation for HTTP parameters, and configuring web application firewalls to detect and block CRLF injection attempts. Additionally, regular security audits of server configurations and logging mechanisms should be conducted to ensure that similar vulnerabilities are not present in other components of the web infrastructure.