Cisco Adaptive Security Appliance Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are available.
A vulnerability in the SIP inspection engine code
could allow an unauthenticated, remote attacker to exhaust available
memory, which may cause instability or a reload of the affected system.
vulnerability is due to improper handling of SIP packets inspected by
the Cisco ASA SIP inspection engine. An attacker could exploit this
vulnerability by sending crafted SIP packets through the affected
system. An exploit could allow the attacker to cause the exhaustion of
available memory. This may cause system instability and in some cases
lead to a reload of the affected system, creating a denial of service
Cisco has confirmed the vulnerability in a security advisory and released software updates.
The following Cisco Adaptive Security Appliance (ASA) Software versions are affected:
Cisco ASA Software versions prior to 8.2(5.48)
Cisco ASA Software versions prior to 8.4(6.5)
Cisco ASA Software versions prior to 9.0(3.1)
Cisco ASA Software versions prior to 9.1(2.5)
To exploit this vulnerability, an attacker may need access to trusted, internal networks in which the targeted device would likely reside to send crafted SIP packets to be processed by the device. This access requirement decreases the likelihood of a successful exploit.
Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.
An unauthenticated, remote attacker could exploit this vulnerability to cause an affected device to consume excessive amounts of available memory resources that may cause the device to reload, resulting in a denial of service (DoS) condition.
The vulnerability is due to improper handling of SIP packets inspected by the SIP inspection engine on a device running an affected version of Cisco ASA Software.
An unauthenticated, remote attacker could exploit this vulnerability by sending crafted SIP packets through the affected system. An exploit could allow the attacker to cause the exhaustion of available memory. This may cause system instability and in some cases lead to a reload of the affected system, creating a denial of service condition.
Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only trusted users to have network access.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
Administrators are advised to monitor affected systems.
Cisco customers with active contracts can obtain updates through the Software Center at the following link: Cisco. Cisco customers without contracts can obtain upgrades by contacting the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via email at firstname.lastname@example.org.
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