ZDI-10-229: ProFTPD TELNET_IAC Remote Code Execution Vulnerability

http://www.zerodayinitiative.com/advisories/ZDI-10-229

November 2, 2010

-- CVSS:
10, (AV:N/AC:L/Au:N/C:C/I:C/A:C)

-- Affected Vendors:
ProFTPD

-- Affected Products:
ProFTPD FTP Server

-- TippingPoint(TM) IPS Customer Protection:
TippingPoint IPS customers have been protected against this
vulnerability by Digital Vaccine protection filter ID 10641.
For further product information on the TippingPoint IPS, visit:

    http://www.tippingpoint.com

-- Vulnerability Details:
This vulnerability allows remote attackers to execute arbitrary code on
vulnerable installations of ProFTPD. Authentication is not required to
exploit this vulnerability.

The flaw exists within the proftpd server component which listens by
default on TCP port 21. When reading user input if a TELNET_IAC escape
sequence is encountered the process miscalculates a buffer length
counter value allowing a user controlled copy of data to a stack buffer.
A remote attacker can exploit this vulnerability to execute arbitrary
code under the context of the proftpd process.

-- Vendor Response:
ProFTPD states:
Patch committed to CVS with accompanying regression test, and backported
to
1.3.3 branch.
http://bugs.proftpd.org/show_bug.cgi?id=3521

-- Disclosure Timeline:
2010-09-24 - Vulnerability reported to vendor
2010-11-02 - Coordinated public release of advisory

-- Credit:
This vulnerability was discovered by:
    * Anonymous

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