Feeds

OpenSSH hits the fan

Get patching!

  • alert
  • submit to reddit

Securing Web Applications Made Simple and Scalable

A serious vulnerability in default installation of OpenSSH on the OpenBSD operating system has come to light.

A vulnerability exists within the "challenge-response" authentication mechanism in the OpenSSH daemon (sshd), according to an alert issued today by Internet Security Systems.

This mechanism, part of the SSH2 protocol, verifies a user's identity by generating a challenge and forcing the user to supply a number of responses.

However this mechanism is flawed in OpenSSH version 3.3 - it's possible for a remote attacker to send a specially-crafted reply that triggers an overflow.

According to ISS, this can result in a remote denial of service attack on the OpenSSH daemon or a complete remote compromise. The OpenSSH daemon runs with superuser privilege, so remote attackers can gain superuser access.

Worse still, the vulnerability is being "actively exploited".

ISS recommends upgrade to OpenSSH version 3.4 immediately. As a workaround, BOFHs might also consider disabling unused OpenSSH authentication mechanisms.

OpenSSH is a free version of the SSH (Secure Shell) communications suite and is used as a secure replacement for protocols such as Telnet, Rlogin, Rsh, and Ftp.

You can find more information about the problem here, and details of vendors which implement OpenSSH here. ®

The smart choice: opportunity from uncertainty

More from The Register

next story
BMW's ConnectedDrive falls over, bosses blame upgrade snafu
Traffic flows up 20% as motorway middle lanes miraculously unclog
Putin: Crack Tor for me and I'll make you a MILLIONAIRE
Russian Interior Ministry offers big pile o' roubles for busting pro-privacy browser
Mozilla fixes CRITICAL security holes in Firefox, urges v31 upgrade
Misc memory hazards 'could be exploited' - and guess what, one's a Javascript vuln
Manic malware Mayhem spreads through Linux, FreeBSD web servers
And how Google could cripple infection rate in a second
How long is too long to wait for a security fix?
Synology finally patches OpenSSL bugs in Trevor's NAS
Don't look, Snowden: Security biz chases Tails with zero-day flaws alert
Exodus vows not to sell secrets of whistleblower's favorite OS
Roll out the welcome mat to hackers and crackers
Security chap pens guide to bug bounty programs that won't fail like Yahoo!'s
prev story

Whitepapers

Top three mobile application threats
Prevent sensitive data leakage over insecure channels or stolen mobile devices.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
Build a business case: developing custom apps
Learn how to maximize the value of custom applications by accelerating and simplifying their development.