Feeds

Crackers exploit Cisco LAN switch flaw

The CatOS is out of the bag

  • alert
  • submit to reddit

Choosing a cloud hosting partner with confidence

Cisco has warned users of a potential denial of service risk involving its popular Catalyst LAN switches.

A buffer overflow vulnerability in Telnet option handling can be used to crash the process and force a Catalyst switch to reload. This operation could be repeated by an attacker to produce a denial of service attack.

Cisco Catalyst switches, series 4000, 5000 and 6000 and also 2948G and 2900 models, running CatOS are affected by the flaw, which is been actively used.

In its notice, Cisco advises: "This vulnerability has been exploited to initiate denial of service (DoS) attacks."

Other Cisco LAN switches and routers are immune, it adds.

The networking giant is offering free software upgrades to affected by the flaw and published a schedule for the availability of fixed releases, which shows fixes will be available by February 4.

Cisco is advising users to upgrade software on affected switches as soon as is becomes available. In the meantime, workarounds to prevent attacks, such as using SSH instead of Telnet, or applying access control lists (ACLs) on routers and firewalls in front of vulnerable boxes, can be applied.

The Catalysts switch vulnerability is related to a flaw involving systems running versions of telnetd derived from BSD source, which was discovered in July last year. At the time this problem was thought to relate mainly to Unix systems, but it is now clear it also affects LAN switches. ®

External links

Cisco Security Advisory: Cisco CatOS Telnet Buffer Vulnerability

Beginner's guide to SSL certificates

More from The Register

next story
FYI: OS X Yosemite's Spotlight tells Apple EVERYTHING you're looking for
It's on by default – didn't you read the small print?
Russian hackers exploit 'Sandworm' bug 'to spy on NATO, EU PCs'
Fix imminent from Microsoft for Vista, Server 2008, other stuff
Microsoft pulls another dodgy patch
Redmond makes a hash of hashing add-on
'LulzSec leader Aush0k' found to be naughty boy not worthy of jail
15 months home detention leaves egg on feds' faces as they grab for more power
China is ALREADY spying on Apple iCloud users, claims watchdog
Attack harvests users' info at iPhone 6 launch
Carders punch holes through Staples
Investigation launched into East Coast stores
Kill off SSL 3.0 NOW: HTTPS savaged by vicious POODLE
Pull it out ASAP, it is SWISS CHEESE
prev story

Whitepapers

Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Cloud and hybrid-cloud data protection for VMware
Learn how quick and easy it is to configure backups and perform restores for VMware environments.
Three 1TB solid state scorchers up for grabs
Big SSDs can be expensive but think big and think free because you could be the lucky winner of one of three 1TB Samsung SSD 840 EVO drives that we’re giving away worth over £300 apiece.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.