Security Adviser | Roger A. Grimes » Huge, Easy Solaris Telnet exploit!

February 11, 2007 | Comments: (0)

Huge, Easy Solaris Telnet exploit!

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If you've got Solaris with Telnet running, you could be in for a big surprise.

Per SANS' announcement:
"If you run Solaris, please check if you got telnet enabled NOW. If you can, block port 23 at your perimeter. There is a fairly trivial Solaris telnet 0-day.

telnet -l "-froot" [hostname]

will give you root on many Solaris systems with default installs We are still testing. Please use our contact form at https://isc.sans.org/contact.html if you have any details about the use of this exploit."

And I thought the Solaris TTYPROMPT telnet exploit of 2002 was easy.

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Johannes Ullrich http://isc.sans.org

Update (2/12/07):
By default the root user cannot telnet to a Solaris box. Root is often prevented from remotely connecting to Unix/Linux boxes in an attempt to prevent some exploits. If root is intentionally prevented from connecting remotely to a box, the admin normally telnets in as another regular user, logs in, and then su's to root. This new exploit should be prevented in default install scenarios (unless admins have commented out the default root blocking text...as many admins do). In those cases, you would need to run the exploit using another valid account (i.e. fbin) with logon privileges instead of froot. Essentially, this means that the exploit is still pretty scary, and pretty easy to pull off.

Posted by Roger Grimes on February 11, 2007 06:39 PM

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