[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20110629180304.GA5060@albatros>
Date: Wed, 29 Jun 2011 22:03:04 +0400
From: Vasiliy Kulikov <segoon@...nwall.com>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
oss-security@...ts.openwall.com, security@...nel.org
Subject: Re: [Security] CVE request: kernel: taskstats/procfs io infoleak
(was: taskstats authorized_keys presence infoleak PoC)
Hi,
One more thing, this is more dangerous, but very conditional.
Create one system account with no files (a victim). This simplifies
measurements.
As an attacker:
Start taskstats listener in the background.
Swith to tty1, push SAK to kill current login task.
Enter some fake username and password, e.g. 1:1.
The login fails, of course.
Now the attacker hides and the victim comes to tty1.
He enters his username:password.
The login succeeds from the first try.
The victim exits from the shell.
Attacker measures login's read_characters value. The victim has to
succeed from the first try and shouldn't push SAK :)
Now the attacker has to increment the fake password length (incrementing
the resulted read_characters of the dead login task) and wait for
the successful victim's login. After ~log2(1024) tries (binary search)
he learns precise password length.
As exiting "login" just waits for the child to exit to call
pam_close_session(), victim's activity doesn't really add any noise.
--
Vasiliy Kulikov
http://www.openwall.com - bringing security into open computing environments
Powered by blists - more mailing lists
Please check out the
Open Source Software Security Wiki, which is counterpart to this
mailing list.
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
