CVE-2008-0263 in Ingate
Summary
by MITRE
The SIP module in Ingate Firewall before 4.6.1 and SIParator before 4.6.1 does not reuse SIP media ports in unspecified call hold and send-only stream scenarios, which allows remote attackers to cause a denial of service (port exhaustion) via unspecified vectors.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 09/14/2018
The vulnerability identified as CVE-2008-0263 affects the Session Initiation Protocol SIP module implementation within Ingate Firewall and SIParator software versions prior to 4.6.1. This issue represents a critical resource exhaustion flaw that specifically impacts the handling of SIP media streams during call hold and send-only scenarios. The vulnerability stems from the software's failure to properly manage and reuse SIP media ports, creating a persistent resource leak that can be exploited by remote attackers to exhaust available port resources. The flaw manifests when SIP sessions enter hold states or transition to send-only stream modes, where the system should theoretically reuse existing media ports but instead maintains them in a persistent state. This behavior creates a significant operational risk as the software continues to allocate new ports without properly releasing the previously used ones, leading to a gradual depletion of available port resources.
The technical implementation of this vulnerability resides in the SIP media port management logic within the firewall's SIP processing module. According to CWE-400, this represents a resource leak vulnerability where the system fails to properly release allocated resources. The flaw specifically impacts the SIP session handling during call hold operations and send-only stream scenarios, which are common in VoIP environments where calls may be placed on hold or transition to audio-only modes. When a SIP session enters these states, the system should release the associated media ports back to the available pool for reuse, but instead maintains them in a held state indefinitely. This improper resource management creates a denial of service condition that can be triggered through various attack vectors including malformed SIP messages, repeated call hold operations, or sustained SIP session manipulation.
The operational impact of this vulnerability extends beyond simple denial of service to potentially disrupt critical communication services within organizations relying on SIP-based voice infrastructure. Attackers can exploit this vulnerability by initiating multiple SIP sessions that enter hold or send-only states, gradually consuming all available media ports until the system can no longer establish new SIP media connections. This creates a cascading effect that can impact not only the specific firewall or SIParator appliance but can also affect downstream VoIP services and communication systems. The vulnerability is particularly dangerous in enterprise environments where SIP traffic is heavy and multiple concurrent sessions are common, as the port exhaustion can occur relatively quickly. The impact aligns with ATT&CK technique T1499.004 which involves resource exhaustion attacks targeting network infrastructure components. Organizations using affected versions may experience complete SIP service disruption, preventing new calls from being established and potentially causing widespread communication failures.
Mitigation strategies for this vulnerability should focus on immediate software updates to versions 4.6.1 or later where the port reuse functionality has been properly implemented. System administrators should also implement network monitoring to detect unusual patterns of port consumption and establish alerts for potential resource exhaustion conditions. Additional protective measures include implementing SIP rate limiting, configuring port pool size restrictions, and deploying network segmentation to isolate critical SIP infrastructure. The fix addresses the core issue by implementing proper port lifecycle management where media ports are released back to the available pool when sessions transition to hold or send-only states. Organizations should also conduct thorough testing of updated systems to ensure that the fix does not introduce compatibility issues with existing SIP infrastructure, particularly in complex VoIP environments with multiple concurrent sessions and various call handling scenarios.