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[SST]ServU MDTM command remote buffero verflow adv
From: icbm (icbm0x557.net)
Date: Sat Jan 24 2004 - 01:49:24 CST
Serv-U Ftp Server Long Filename Stack Overflow Vunlnerablity
Affected Versions: All versions prior 4.2 (include 126.96.36.199)
Vendor: RhinoSoft (http://www.rhinosoft.com
An internal memory buffer may be overrun while handling "site chmod" command
with a filename containg excessive data. This condition may be exploited by
attackers to ultimately execute instructions with the priviledges of the serv-u
process, typically administator or system.
While exectuing chmod on a nonexistent file, serv-u will call sprintf to
construct response string. And the code is like
sprintf(dst, "%s: No such file or directory.", filename);
The length of dst buffer is only 256 bytes.If a long filename was sent,
serv-u will crash.
A writable directory is needed to exploit this vulerablity.By overwriting SEH,
we have created proof-of-concept exploit successfully on win2k/xp.
Upgrade to servu 5.0.
kkqq <kkqq0x557.org> has indenpendently discovered this vulerablity.
All members of SST (http://www.0x557.org).
lgx and eyas.
Rob Beckers for indentifing and fixing this vulerablity.
Do we really exist?