CVE-2010-3711 in Pidgin
Summary
by MITRE
libpurple in Pidgin before 2.7.4 does not properly validate the return value of the purple_base64_decode function, which allows remote authenticated users to cause a denial of service (NULL pointer dereference and application crash) via a crafted message, related to the plugins for MSN, MySpaceIM, XMPP, and Yahoo! and the NTLM authentication support.
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Analysis
by VulDB Data Team • 12/08/2024
The vulnerability identified as CVE-2010-3711 represents a critical denial of service flaw within the libpurple library component of Pidgin messaging client versions prior to 2.7.4. This vulnerability specifically targets the improper validation of return values from the purple_base64_decode function, creating a condition where authenticated remote attackers can exploit the application's handling of malformed base64 encoded data. The flaw affects multiple instant messaging protocols including MSN, MySpaceIM, XMPP, and Yahoo! protocols, as well as NTLM authentication support mechanisms within the messaging framework. The vulnerability stems from insufficient input validation and error handling within the core messaging library that processes incoming messages from remote peers.
The technical implementation of this vulnerability exploits a NULL pointer dereference condition that occurs when the purple_base64_decode function returns an invalid or NULL value that is subsequently dereferenced without proper validation. When processing crafted messages containing malformed base64 encoded data, the application fails to verify that the decoding operation produces valid output before attempting to use the result. This flaw manifests across multiple protocol plugins because they all utilize the same underlying libpurple base64 decoding functionality, creating a widespread impact that affects various communication channels. The vulnerability is classified under CWE-476 as a NULL Pointer Dereference, which represents a fundamental error handling weakness where program code fails to check for NULL return values from functions that may legitimately return NULL under certain conditions.
From an operational perspective, this vulnerability creates significant disruption potential for users and organizations relying on Pidgin for instant messaging communications. The denial of service condition results in application crashes that require manual restart of the messaging client, potentially interrupting important communications and requiring user intervention to restore service. The authenticated nature of the attack means that malicious users must already have valid credentials to target other users, but this limitation does not mitigate the impact since legitimate users may be targeted by compromised accounts or attackers who have obtained valid credentials through other means. The vulnerability affects both individual users and enterprise environments where Pidgin may be deployed as part of communication infrastructure, potentially leading to service availability issues during critical communication periods.
The impact of this vulnerability extends beyond simple application crashes to represent a broader concern for message integrity and system stability within instant messaging platforms. Attackers can exploit this weakness to disrupt communications without requiring elevated privileges or complex attack vectors, making it particularly dangerous in environments where reliable messaging is critical. The vulnerability's presence in core authentication support mechanisms like NTLM further amplifies the risk since it could potentially be used to disrupt authentication flows between clients and servers. Organizations implementing security controls should consider this vulnerability as part of their broader application security posture, particularly in environments where Pidgin is used for business communications. The flaw demonstrates the importance of proper input validation and error handling in security-critical components, as outlined in ATT&CK technique T1499 for Network Denial of Service and T1566 for Credential Access through authentication system exploitation.
Mitigation strategies for this vulnerability center on immediate patching of affected Pidgin installations to version 2.7.4 or later, which contains the necessary code fixes to properly validate base64 decoding return values. Network administrators should also implement monitoring for unusual message patterns that might indicate exploitation attempts, particularly around base64 encoded content in messaging protocols. The vulnerability serves as a reminder of the critical importance of proper error handling in security libraries, as the fix involves ensuring that all return values from cryptographic and encoding functions are properly validated before use. Organizations should also consider implementing message filtering mechanisms that can detect and block suspicious base64 encoded content patterns as an additional defensive measure. Regular security assessments of messaging infrastructure and application libraries should include verification of proper input validation and error handling practices to prevent similar vulnerabilities from emerging in other components of the communication stack.