CVE-2002-2286 in apt-www-proxy
Summary
by MITRE
The parse-get function in utils.c for apt-www-proxy 0.1 allows remote attackers to cause a denial of service (crash) via an empty HTTP request, which causes a null dereference.
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Analysis
by VulDB Data Team • 06/12/2018
The vulnerability identified as CVE-2002-2286 resides within the apt-www-proxy software version 0.1, specifically in the parse-get function located in the utils.c source file. This flaw represents a classic null pointer dereference issue that can be exploited by remote attackers to trigger a denial of service condition. The attack vector is particularly insidious as it requires only a malformed HTTP request containing no data to execute successfully. When the proxy receives such an empty HTTP request, the parse-get function attempts to process the input without proper validation, leading to a null pointer dereference that ultimately causes the application to crash and terminate unexpectedly.
From a technical perspective, this vulnerability operates at the application layer and demonstrates poor input validation practices that are commonly associated with CWE-476, which specifically addresses null pointer dereference conditions. The flaw occurs because the function fails to properly handle edge cases where HTTP requests contain no content or minimal data, creating a scenario where the application assumes certain data structures will contain valid pointers while they actually contain null values. This type of vulnerability falls under the broader category of software defects that can be mitigated through proper defensive programming practices and comprehensive input validation mechanisms. The attack pattern aligns with techniques described in the ATT&CK framework under the T1499.004 subtechnique related to network denial of service, where adversaries exploit application-level vulnerabilities to disrupt service availability.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be leveraged by attackers to systematically degrade the availability of the apt-www-proxy service. Since the vulnerability requires only an empty HTTP request to trigger, it can be easily exploited through automated tools or simple network scanning activities, making it particularly dangerous in environments where such proxies are critical for package management operations. Organizations relying on apt-www-proxy for managing software updates and package distribution could experience significant operational disruptions when this vulnerability is exploited, potentially affecting multiple systems that depend on the proxy for accessing package repositories. The crash condition not only prevents legitimate users from accessing package management services but also creates potential logging and monitoring issues that could mask the actual attack activity.
Mitigation strategies for this vulnerability should focus on implementing robust input validation and defensive programming practices within the affected application. The most effective immediate solution involves patching the parse-get function to properly validate HTTP request content before attempting to process it, ensuring that null pointers are checked and handled gracefully rather than allowing the application to crash. Organizations should also consider implementing rate limiting and request validation mechanisms at network boundaries to prevent exploitation attempts. Additionally, deploying intrusion detection systems that can identify and block malformed HTTP requests may provide an additional layer of defense. The fix should be implemented following secure coding guidelines that emphasize proper error handling and input validation, ensuring that all pointers are validated before dereferencing and that appropriate error responses are returned instead of allowing application crashes to occur. Regular security audits and code reviews should be conducted to identify similar patterns that could lead to null pointer dereference vulnerabilities in other components of the system.