Cisco issues 16 patches to pop pesky peccant packets

Remote code execution for some, denial of service for the rest of us

Cisco has issued a string of patches for 16 faults including a fix for a possible remote code execution in its IOS and IOS XE routing software.

The patches address a generous dollop of security conditions caused by faulty queued packets.

One flaw, rated severity 8.3, allows attackers to gain remote code execution in IOS XE by sending a crafted packet that allows code to run on affected boxes.

Attackers could also send crafted packets to trigger denial of service.

"A vulnerability in the AppNav component of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload and may allow arbitrary code execution on the affected system," Cisco says in its advisory.

"The vulnerability is due to improper processing of crafted TCP packets. An attacker could exploit this vulnerability by sending a crafted TCP packet that needs to be processed by the AppNav component configured on an affected device. An exploit could allow the attacker to cause an affected device to reload or execute arbitrary code in the forwarding engine."

Another fix addresses flaws that allow attackers to spoof Autonomic Networking Registration Authority response thanks to lax message validation

"A successful exploit could allow an attacker to bootstrap a device into an untrusted autonomic domain, gaining limited command and control of the AN node, causing a denial of service condition and disrupting access to the legitimate autonomic domain," Cisco says .

Further vulnerabilities coupled in that advisory lead to denial of service conditions.

The Borg also closed off a medium-severity vulnerability (CVE-2015-0769) in the IOS XR carrier software rated 5 can be easily exploited by attackers sending a packet that would thanks to IPv6 extension headers trigger denial of service.

It says this occurs because the headers are not typical of normal operation and says there are no work-arounds for the flaw meaning affected systems will require the patch.

"A vulnerability in the IP version 6 processing code of Cisco IOS XR Software for Cisco CRS-3 Carrier Routing System could allow an unauthenticated, remote attacker to trigger an ASIC scan of the Network Processor Unit and a reload of the line card processing an IPv6 packet," it says in an advisory.

"The vulnerability is due to incorrect processing of an IPv6 packet carrying IPv6 extension headers that are valid but unlikely to be seen during normal operation.

"An attacker could exploit this vulnerability by sending such an IPv6 packet to an affected device that is configured to process IPv6 traffic."

That exploit can cause a reload of the line card triggering repeated denial of service through transit traffic or data destined for the device.

Affected Cisco IOS XR versions include 4.0.1; 40.2; 4.0.3; 4.0.4; 4.1.0; 4.1.1; 4.1.2, and 4.2.0.

IOS XR Release 4.2.1 and later are not affected. ®

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