A vulnerability in HTTP Deep Packet Inspection (DPI) code could allow an unauthenticated, remote attacker to cause a reload of the affected system.
The vulnerability is due to improper handling of a race condition when the HTTP DPI engine is inspecting HTTP packets and either the spoof-server parameters option is enabled or the Cisco ASA Software is configured to inspect and mask the HTTP response including active-x or java-applet in the response body. An attacker could exploit this vulnerability by sending a crafted HTTP response through the affected system.
Cisco has confirmed the vulnerability in a security advisory and released software updates.
Indicators of Compromise
Cisco Adaptive Security Appliance Software versions prior to 8.2(5.46), 8.3(2.39), 8.4(5.6), 8.5(1.18), 8.6(1.12), 8.7(1.4), 9.0(1.4), and 9.1(1.2) are vulnerable.
The vulnerability is due to improper handling of packets by the HTTP Deep Packet Inspection engine when the spoof-server parameter is enabled or the software is configured to mask HTTP responses.
An unauthenticated, remote attacker could exploit this vulnerability by sending a series of malicious HTTP packets designed to transit the vulnerable device. The inspection of the HTTP packets could cause the device to reload, resulting in a DoS condition.
Only devices using HTTP inspection are vulnerable. Attackers may also require a privileged position in the network. These factors reduce the potential for exploitation.
Administrators are advised to apply the appropriate updates.
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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Cisco Multivendor Vulnerability Alerts respond to vulnerabilities identified in third-party vendors' products. These alerts contain information compiled from diverse sources and provide comprehensive technical descriptions, objective analytical assessments, workarounds and practical safeguards, and links to vendor advisories and patches.