CVE-2016-10189 in BitlBee
Summary
by MITRE
BitlBee before 3.5 allows remote attackers to cause a denial of service (NULL pointer dereference and crash) and possibly execute arbitrary code via a file transfer request for a contact that is not in the contact list.
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Analysis
by VulDB Data Team • 03/15/2017
The vulnerability identified as CVE-2016-10189 affects BitlBee versions prior to 3.5, representing a critical security flaw that exposes the application to remote attack vectors through improper input validation during file transfer operations. This vulnerability manifests as a NULL pointer dereference condition that can be triggered when the application processes file transfer requests for contacts not present in its contact list. The flaw originates from inadequate boundary checking and validation mechanisms within the file transfer handling code, where the application fails to properly validate the existence of a contact before attempting to access associated data structures.
The technical implementation of this vulnerability involves a specific code path where BitlBee processes incoming file transfer requests without verifying whether the requesting contact exists in the local contact database. When a remote attacker sends a file transfer request for a non-existent contact, the application attempts to dereference a NULL pointer that should have been validated, leading to an immediate crash of the service. This crash scenario represents a classic denial of service condition that can be exploited repeatedly to maintain service unavailability. However, the vulnerability extends beyond simple DoS by potentially allowing arbitrary code execution through careful exploitation of the memory corruption that occurs during the NULL pointer dereference, making it a particularly dangerous flaw in the context of remote attacker scenarios.
The operational impact of this vulnerability extends significantly beyond simple service disruption, as it creates a persistent threat vector that can be leveraged by malicious actors to gain unauthorized access to systems running vulnerable BitlBee instances. The vulnerability affects systems that rely on BitlBee for instant messaging and communication protocols, particularly those used in enterprise environments where the application serves as a bridge between various messaging platforms. Attackers can exploit this flaw by simply initiating a file transfer request to a non-existent contact, requiring minimal technical expertise or resources to execute successfully. This makes the vulnerability particularly attractive for automated exploitation campaigns targeting organizations with vulnerable installations.
The vulnerability aligns with CWE-476, which specifically addresses NULL pointer dereference conditions in software implementations, and demonstrates how inadequate input validation can create cascading failures in application security. From an ATT&CK framework perspective, this vulnerability maps to the T1203 - Exploitation for Client Execution technique, as it allows for arbitrary code execution through client-side application flaws, and potentially to T1499 - Endpoint Denial of Service, given the crash and service disruption capabilities. Organizations using BitlBee in production environments face significant risk from this vulnerability, as it can be exploited remotely without authentication requirements, making it particularly dangerous for systems that are exposed to untrusted networks or external communication channels.
Mitigation strategies for this vulnerability center on immediate patch deployment to BitlBee version 3.5 or later, which includes proper input validation and NULL pointer checks for file transfer operations. System administrators should implement network segmentation to limit exposure of BitlBee services to untrusted networks, while also monitoring for suspicious file transfer activity that might indicate exploitation attempts. Additional protective measures include implementing strict access controls for file transfer capabilities, disabling unnecessary file transfer features when not required, and maintaining comprehensive network monitoring to detect anomalous behavior patterns that might indicate exploitation attempts. Organizations should also consider implementing intrusion detection systems with signatures specific to this vulnerability to provide early warning of potential exploitation attempts.