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roger_grimes
Columnist

Huge, Easy Solaris Telnet exploit!

Analysis
Feb 12, 20072 mins
Data and Information SecuritySecurity

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:

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.

———–

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.

roger_grimes
Columnist

Roger A. Grimes is a contributing editor. Roger holds more than 40 computer certifications and has authored ten books on computer security. He has been fighting malware and malicious hackers since 1987, beginning with disassembling early DOS viruses. He specializes in protecting host computers from hackers and malware, and consults to companies from the Fortune 100 to small businesses. A frequent industry speaker and educator, Roger currently works for KnowBe4 as the Data-Driven Defense Evangelist and is the author of Cryptography Apocalypse.

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