Feeds

Cisco patches DoS vuln pair in IOS

No exploit spotted

High performance access to file storage

Cisco has issued a pair of updates today patching two remote denial of service vulnerabilities affecting certain devices running its Internetwork Operating System (IOS).

The vulnerabilities are limited to kit running Cisco IOS software with support for four-octet Autonomous Systems number space (AKA: 4-byte AS number) and Border Gateway Protocal (BGP) routing configured. Attackers could use the exploits for repeated reloading of the device causing an extended denial of service blockage.

The security holes were confirmed in Cisco IOS and Cisco IOS XE with support for RFC4893.

The first vulnerability may cause an affected device to crash with memory corruption, but requires three conditions:

  • Cisco IOS Software device is a 4-byte AS number BGP speaker
  • BGP peering neighbor is a 2-byte AS number BGP speaker
  • BGP peering neighbor is capable of sending a BGP update with a series of greater than one thousand AS numbers

If an affected 4-byte AS number BGP speaker receives a BGP update from a 2-byte AS number BGP speaker containing AS path segments of more than one thousand autonomous systems, the device may crash with memory corruption and spit out the error "%%Software-forced reload."

Cisco says there is no workarounds on the affected device, but neighbors could be configured to discard routes that have more than one thousand AS numbers in the AS-path segment.

The second vulnerability could cause a device to reload when it processes a malformed BGP update that has been designed to trigger the issue.

This security hole requires three conditions as well:

  • Cisco IOS Software device is a 4-byte AS number BGP speaker
  • BGP peering neighbor is a 2-byte AS number BGP speaker
  • BGP peering neighbor is capable of sending a non-RFC complaint malicious BGP update message.

Cisco says configuring "bgp maxas-limited [value]" on the affected device will mitigate the vulnerability. The company suggests using a lowball value of 100 to best avoid the problem.

Updates have been issued to stop the vulnerabilities, and of course users are advised to update to the fixed version. Cisco said its not aware of anyone maliciously exploiting the security flaws, although some customers have accidentally triggered the first vulnerability within their infrastructures.

Additional details are available on the security notice here. ®

High performance access to file storage

More from The Register

next story
Obama allows NSA to exploit 0-days: report
If the spooks say they need it, they get it
Parent gabfest Mumsnet hit by SSL bug: My heart bleeds, grins hacker
Natter-board tells middle-class Britain to purée its passwords
Web data BLEEDOUT: Users to feel the pain as Heartbleed bug revealed
Vendors and ISPs have work to do updating firmware - if it's possible to fix this
OpenSSL Heartbleed: Bloody nose for open-source bleeding hearts
Bloke behind the cockup says not enough people are helping crucial crypto project
One year on: diplomatic fail as Chinese APT gangs get back to work
Mandiant says past 12 months shows Beijing won't call off its hackers
Call of Duty 'fragged using OpenSSL's Heartbleed exploit'
So it begins ... or maybe not, says one analyst
Experian subsidiary faces MEGA-PROBE for 'selling consumer data to fraudster'
US attorneys general roll up sleeves, snap on gloves
NSA denies it knew about and USED Heartbleed encryption flaw for TWO YEARS
Agency forgets it exists to protect communications, not just spy on them
prev story

Whitepapers

Mainstay ROI - Does application security pay?
In this whitepaper learn how you and your enterprise might benefit from better software security.
Five 3D headsets to be won!
We were so impressed by the Durovis Dive headset we’ve asked the company to give some away to Reg readers.
3 Big data security analytics techniques
Applying these Big Data security analytics techniques can help you make your business safer by detecting attacks early, before significant damage is done.
The benefits of software based PBX
Why you should break free from your proprietary PBX and how to leverage your existing server hardware.
Mobile application security study
Download this report to see the alarming realities regarding the sheer number of applications vulnerable to attack, as well as the most common and easily addressable vulnerability errors.