This is (obviously) a format string vulnerability. (Un)fortunately war-ftpd.exe
has it's own implementation of printf-functions that doesn't support "%n" -> No
arbitrary overwrites.
The formatstring and destination string are on the heap and the destination is
dynamically allocated --> no buffer overflows.
All in all: no code execution.
Vulnerabilities:
Commands such as "USER %9999999999d%9999999999d%999999999999d" will consume a
lot of CPU and memory, thus causing a DoS on the system and not just War-ftpd.
(Maybe Secunia want to update their rating again.)
Commands such as "USER %s%s%s%s%s....%s%s" are bound to run into a dword that
doesn't point to allocated memory, thus causing a DoS on War-ftpd itself.
To exploit this format string vuln, the target War-ftpd.exe needs to run as a
service since it resides in one of the logging functions that it only uses when
running as a service.
Cheers,
SkyLined
Berend-Jan Wever <skylined@edup.tudelft.nl>
TTP: http://www.edup.tudelft.nl/~bjwever
MSN: skylined@edup.tudelft.nl
IRC: SkyLined in #SkyLined on EFNET
PGP: key ID 0x48479882
----- Original Message -----
From: "class 101" <class101@hat-squad.com>
To: <full-disclosure@lists.netsys.com>
Sent: Friday, January 28, 2005 18:58
Subject: [Full-Disclosure] War-ftpd bug small addition
To fix the buggus advisory spreaded everywhere saying that you need to be
authenticated, It's false Mc.Iglo ;)
USER %s*115AAAAA
PASS blahblah
http://secunia.com/advisories/14054/
-------------------------------------------------------------
class101
Jr. Researcher
Hat-Squad.com
-------------------------------------------------------------
--------------------------------------------------------------------------------
_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.netsys.com/full-disclosure-charter.html
_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.netsys.com/full-disclosure-charter.html
