The Zone-Based Firewall (ZFW) feature in Cisco IOS 15.1 through 15.2, when content filtering or HTTP ALG inspection is enabled, allows remote attackers to cause a denial of service (device reload or hang) via crafted IPv4 HTTP traffic, aka Bug ID CSCtx56174.

The Zone-Based Firewall (ZFW) feature in Cisco IOS 15.1 through 15.2, when content filtering or HTTP ALG inspection is enabled, allows remote attackers to cause a denial of service (device reload or hang) via crafted IPv4 HTTP traffic, aka Bug ID CSCtx56174.

The Zone-Based Firewall (ZFW) feature in Cisco IOS 15.1 through 15.2, when content filtering or HTTP ALG inspection is enabled, allows remote attackers to cause a denial of service (device reload or hang) via crafted IPv4 HTTP traffic, aka Bug ID CSCtx56174. Cisco IOS is the interconnected network operating system used on most Cisco system routers and network switches. A security vulnerability exists in the Cisco IOS domain-based firewall component that allows unauthenticated remote attackers to suspend or reload affected devices. If the device is configured with content filtering or HTTP application layer gateway detection, the attacker sends a specific HTTP packet to the affected device to trigger the vulnerability. The vulnerability can be successfully used to suspend the device or Overloading, causing a denial of service attack. The following devices are affected by this vulnerability: Cisco IOS 15.1 GC 15.1(4)GC, 15.1(4)GC1 | 15.1M 15.1(4)M2, 15.1(4)M3, 15.1(4)M3a, 15.1(4)M4, 15.1( 4) M5 | 15.1XB 15.1(4)XB6, 15.1(4)XB7, 15.1(4)XB8a | 15.2GC 15.2(1)GC, 15.2(1)GC1, 15.2(1)GC2, 15.2(2)GC, 15.2(3)GC, 15.2(3)GC1 | 15.2GCA 15.2(3)GCA | 15.2T 15.2(1)T, 15.2(1)T1, 15.2(1)T2, 15.2(1)T3, 15.2(1) T3a, 15.2(2)T, 15.2(2)T1, 15.2(2)T2, 15.2(2)T3, 15.2(2)T4, 15.2(3)T, 15.2(3)T1, 15.2(3)T2, 15.2(3)T3 | 15.2XA 15.2(3)XA. Cisco IOS is prone to a remote denial-of-service vulnerability. Exploiting this issue may allow remote attackers to trigger denial-of-service conditions. This issue i…