GRE Route Option resolution overflow vulnerability in Cisco IOS

Affected Systems:

Cisco IOS 12.2

Cisco IOS 12.1

Cisco IOS 12.0

Description:

Cisco Internet OS IOS) is the operating system used by Cisco devices.

Cisco Systems IOS has a vulnerability in parsing GRE packets containing GRE source route information. Remote attackers may cause devices to process packets incorrectly.

If a specially crafted GRE message is received, the IOS device does not verify whether the offset field points to the message. If the offset value is set to a negative value, IOS directly removes the offset from the integer that contains the full length of IP packets, leading to cross-border access overflow in the buffer zone.

If the ring buffer can be carefully filled by legal communication with an IP header at an appropriate offset, attackers can create a large length of IP packets in IOS.

Vendor patch:

Cisco

Currently, the vendor has released

Upgrade the patch to fix this security problem, please go to the vendor's home page download: http://www.cisco.com/

(T113)