Feeds

Back Orifice for Unix flaw emerges from obscurity

Mind the gap

  • alert
  • submit to reddit

Choosing a cloud hosting partner with confidence

A vulnerability involving an obscure UDP protocol might permits crackers to obtain remote control of Unix workstations, security experts have warned.

Security firm ProCheckUp has issued an advisory warning that anonymous XDMCP connections allow remote attackers to obtain a remote console identical to a local X-Windows session, using a command enabled by default on most Unix boxes.

Richard Brain, ProCheckUp's technical director, described the flaw as a "Back Orifice
for Unix" because it might permit anonymous attackers to shut down or gain remote control of a victim's machine. This seems slightly overstated because there are a number of mitigating factors.

To exploit the vulnerability an attacker would still need to guess the correct X-Windows password, but given the lame passwords many users pick this is hardly a high enough barrier.

A properly configured firewall will block the UDP session but that too won't protect everyone - particularly when you consider a tool that scans for XDMCP traffic has become available on the Internet.

Worrying.

Because of the existence of this utility ProCheckUp has released a notice on the vulnerability ahead of security patches from vendors or complete testing on all platforms the flaw might affect. It seems the vulnerability has existed for some time but was dismissed because of assumptions about hardware, software and the possibilities of hacking them, that have now been called into question.

This flaw appears to affect all versions of Sun Solaris and versions of Linux Mandrake up to 8.1, though Red Hat Linux is believed to be immune to that attack. The jury is out on IBM's AIX and HP/UX.

Admins can guard against the problem by implementing workarounds such as disabling remote connection and blocking traffic on ports used by the XDMCP protocol. This is explained in more detail in ProCheckUp's advisory here. ®

Secure remote control for conventional and virtual desktops

More from The Register

next story
Regin: The super-spyware the security industry has been silent about
NSA fingered as likely source of complex malware family
Why did it take antivirus giants YEARS to drill into super-scary Regin? Symantec responds...
FYI this isn't just going to target Windows, Linux and OS X fans
Privacy bods offer GOV SPY VICTIMS a FREE SPYWARE SNIFFER
Looks for gov malware that evades most antivirus
Patch NOW! Microsoft slings emergency bug fix at Windows admins
Vulnerability promotes lusers to domain overlords ... oops
HACKERS can DELETE SURVEILLANCE DVRS remotely – report
Hikvision devices wide open to hacking, claim securobods
'Regin': The 'New Stuxnet' spook-grade SOFTWARE WEAPON described
'A degree of technical competence rarely seen'
Astro-boffins start opening universe simulation data
Got a supercomputer? Want to simulate a universe? Here you go
You stupid BRICK! PCs running Avast AV can't handle Windows fixes
Fix issued, fingers pointed, forums in flames
prev story

Whitepapers

Driving business with continuous operational intelligence
Introducing an innovative approach offered by ExtraHop for producing continuous operational intelligence.
Why CIOs should rethink endpoint data protection in the age of mobility
Assessing trends in data protection, specifically with respect to mobile devices, BYOD, and remote employees.
Getting started with customer-focused identity management
Learn why identity is a fundamental requirement to digital growth, and how without it there is no way to identify and engage customers in a meaningful way.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Simplify SSL certificate management across the enterprise
Simple steps to take control of SSL across the enterprise, and recommendations for a management platform for full visibility and single-point of control for these Certificates.