CVE-2007-1306 in Asterisk
Summary
by MITRE
Asterisk 1.4 before 1.4.1 and 1.2 before 1.2.16 allows remote attackers to cause a denial of service (crash) by sending a Session Initiation Protocol (SIP) packet without a URI and SIP-version header, which results in a NULL pointer dereference.
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Analysis
by VulDB Data Team • 11/25/2024
The vulnerability identified as CVE-2007-1306 represents a critical denial of service flaw within the Asterisk telephony platform, specifically affecting versions prior to 1.4.1 and 1.2.16. This vulnerability resides in the Session Initiation Protocol (SIP) handling mechanism, which is fundamental to voice over IP communications. The flaw manifests when the Asterisk server receives a malformed SIP packet that lacks both the URI and SIP-version header fields, creating a scenario where the application fails to properly validate incoming SIP messages before processing them.
The technical root cause of this vulnerability stems from insufficient input validation within the SIP parser component of Asterisk. When a SIP packet arrives without the required URI and SIP-version headers, the application attempts to dereference a NULL pointer during the message processing cycle. This NULL pointer dereference occurs because the software assumes these headers will always be present and does not implement proper null checks before accessing memory locations. The vulnerability is classified under CWE-476 as a NULL pointer dereference, which is a common programming error that can lead to application crashes and system instability. This type of error typically occurs when software developers fail to validate input data before using it in memory operations, creating a pathway for malicious actors to exploit the system's lack of defensive programming practices.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be leveraged by remote attackers to systematically crash Asterisk servers without requiring any authentication or privileged access. This makes the vulnerability particularly dangerous in production environments where telephony services are critical to business operations. When exploited, the denial of service condition causes the Asterisk process to terminate unexpectedly, resulting in complete loss of telephony services until the system is manually restarted. The attack vector is particularly concerning because it requires minimal effort from an attacker - simply sending a malformed SIP packet is sufficient to trigger the crash. This vulnerability can be amplified through automated tools that can send multiple malformed packets in rapid succession, potentially leading to sustained service disruption and significant business impact.
Mitigation strategies for this vulnerability should focus on immediate software updates to versions 1.4.1 and 1.2.16 or later, which contain the necessary patches to properly validate incoming SIP packets and handle missing headers gracefully. Network administrators should also implement SIP message filtering mechanisms at the firewall or proxy level to detect and block malformed SIP packets before they reach the Asterisk server. Additionally, configuring intrusion detection systems to monitor for unusual SIP traffic patterns can help identify potential exploitation attempts. The ATT&CK framework categorizes this vulnerability under the T1499.004 technique for "Endpoint Denial of Service" as it involves exploiting application-level flaws to cause system crashes. Organizations should also consider implementing redundant telephony systems and automated failover mechanisms to minimize the impact of such attacks on business continuity. Regular security assessments and vulnerability scanning should be conducted to identify similar input validation weaknesses in other network services and applications that may be vulnerable to similar NULL pointer dereference attacks.