CVE-2008-4776 in libgadu
Summary
by MITRE
libgadu before 1.8.2 allows remote servers to cause a denial of service (crash) via a contact description with a large length, which triggers a buffer over-read.
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Analysis
by VulDB Data Team • 08/20/2019
The vulnerability identified as CVE-2008-4776 affects the libgadu library version 1.8.1 and earlier, representing a critical buffer over-read flaw that can be exploited by remote servers to induce denial of service conditions. This library serves as a core component for instant messaging protocols, particularly within the Gadu-Gadu messaging system which was widely used in Poland and other European regions. The flaw manifests when the library processes contact descriptions containing excessively long data payloads, creating a scenario where memory access boundaries are exceeded during data parsing operations.
The technical implementation of this vulnerability resides in the improper validation and handling of input data within the libgadu library's parsing routines. When a remote server sends a contact description with an abnormally large length parameter, the library fails to adequately bound-check the data before attempting to read or process it. This buffer over-read condition occurs because the library allocates memory buffers based on expected data sizes but does not validate that incoming data conforms to acceptable length parameters. The flaw specifically targets the contact description field processing mechanism, where the library attempts to read beyond allocated memory boundaries, potentially causing application crashes or system instability.
The operational impact of this vulnerability extends beyond simple service disruption to encompass potential system compromise and reliability degradation. Remote attackers can exploit this flaw by crafting malicious contact descriptions with oversized data fields, leading to application crashes that may result in complete service unavailability. In environments where libgadu is integrated into critical messaging infrastructure, such as enterprise communication systems or web-based instant messaging services, this vulnerability could lead to extended downtime and service interruption. The vulnerability also presents potential for escalation if the buffer over-read conditions can be manipulated to execute arbitrary code, though the primary impact remains focused on denial of service operations.
Mitigation strategies for CVE-2008-4776 primarily involve immediate software updates and implementation of input validation measures. The most effective solution requires upgrading to libgadu version 1.8.2 or later, which includes proper bounds checking and input validation mechanisms. System administrators should also implement network-level filtering to restrict incoming contact description data to reasonable length parameters and deploy intrusion detection systems that can identify and block suspicious data patterns. Additionally, application-level input sanitization should be implemented to validate all contact description fields before processing, ensuring that length parameters remain within expected operational ranges. This vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and represents a classic example of improper input validation that can lead to denial of service attacks. The ATT&CK framework categorizes this vulnerability under T1499.004, specifically targeting application or system recovery through service disruption, making it a significant concern for network security operations and incident response protocols.