CVE-2006-5876 in libsoup
Summary
by MITRE
The soup_headers_parse function in soup-headers.c for libsoup HTTP library before 2.2.99 allows remote attackers to cause a denial of service (crash) via malformed HTTP headers, probably involving missing fields or values.
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Analysis
by VulDB Data Team • 07/13/2019
The vulnerability identified as CVE-2006-5876 resides within the libsoup HTTP library, specifically in the soup_headers_parse function located in soup-headers.c. This critical flaw affects versions prior to 2.2.99 and represents a classic buffer over-read or parsing error that can be exploited by remote attackers to trigger a denial of service condition. The vulnerability manifests when the library encounters malformed HTTP headers during the parsing process, particularly those with missing fields or values that the function does not properly handle. This issue falls under the category of improper input validation and can be classified as a CWE-121 buffer overflow or CWE-129 improper validation of array indices, both of which are fundamental security weaknesses that have plagued software libraries for decades.
The operational impact of this vulnerability extends beyond simple service disruption as it can be leveraged by attackers to crash applications that utilize the libsoup library for HTTP communications. When a remote attacker crafts malicious HTTP headers containing malformed field structures or missing values, the soup_headers_parse function fails to properly validate the input before attempting to process it, leading to a crash or segmentation fault in the affected application. This behavior aligns with ATT&CK technique T1499.004 for network denial of service and can be particularly dangerous in web servers, proxy applications, or any HTTP client that relies on libsoup for header processing. The vulnerability's exploitation requires minimal privileges and can be executed remotely, making it a significant threat to systems that handle HTTP traffic from untrusted sources.
Systems utilizing the affected libsoup versions are particularly vulnerable in environments where HTTP traffic is processed without proper input sanitization or where the library is used in server-side applications that accept headers from potentially malicious clients. The attack surface is broad as libsoup is used in various applications including web browsers, email clients, web servers, and proxy services that require HTTP protocol handling capabilities. Organizations running applications such as GNOME web browsers, Evolution email clients, or any software that integrates libsoup for HTTP communications are at risk. The vulnerability's classification under CWE-121 and CWE-129 indicates that it involves improper handling of input data structures, where the function fails to validate header field boundaries or handle missing values gracefully, leading to memory access violations. Mitigation strategies should include immediate upgrading to libsoup version 2.2.99 or later, implementing input validation at the application level, and deploying network-based intrusion detection systems to monitor for suspicious HTTP header patterns. Additionally, security teams should consider implementing application firewalls or web application firewalls that can detect and block malformed HTTP header sequences that may indicate exploitation attempts.