rdesktop Integer Underflow in iso_recv_msg() Lets Remote Users Execute Arbitrary Code
SecurityTracker Alert ID: 1019990|
SecurityTracker URL: http://securitytracker.com/id/1019990
(Links to External Site)
Date: May 8 2008
Execution of arbitrary code via network, User access via network|
Fix Available: Yes Vendor Confirmed: Yes |
A vulnerability was reported in rdesktop. A remote user can execute arbitrary code on the target system.|
A remote RDP server can send a specially crafted reply to the connected target user to trigger an integer underflow and execute arbitrary code on the target user's system. The code will run with the privileges of the target user.
The vulnerability resides in the iso_recv_msg() function in 'iso.c'.
The vendor was notified on November 12, 2007.
An anonymous researcher reported this vulnerability via iDefense.
A remote server can execute arbitrary code on the connected target user's system.|
The vendor has issued a source code fix, available at:|
Vendor URL: www.rdesktop.org/ (Links to External Site)
|Underlying OS: Linux (Any), UNIX (Any)|
This archive entry has one or more follow-up message(s) listed below.|
Source Message Contents
Subject: iDefense Security Advisory 05.07.08: Multiple Vendor rdesktop|
iDefense Security Advisory 05.07.08
May 07, 2008
rdesktop is an open source client that speaks the Remote Desktop
Protocol (RDP). This allows Unix-based users to login to Windows
Terminal Servers. More information is available at the following URL.
Remote exploitation of an integer underflow vulnerability in rdesktop,
as included in various vendors' operating system distributions, allows
attackers to execute arbitrary code with the privileges of the
The vulnerability exists within the code responsible for reading in an
RDP request. When reading a request, a 16-bit integer value that
represents the number of bytes that follow is taken from the packet.
This value is then decremented by 4, and used to calculate how many
bytes to read into a heap buffer. The subtraction operation can
underflow, which will then lead to the heap buffer being overflowed.
Exploitation of this vulnerability results in the execution of arbitrary
code with the privileges of the logged in user. In order to exploit this
vulnerability, an attacker must persuade a targeted user to connect to a
malicious RDP server.
iDefense confirmed the existence of this vulnerability in rdesktop
version 1.5.0. Previous versions may also be affected.
iDefense is currently unaware of any effective workaround for this
VI. VENDOR RESPONSE
The rdesktop maintainer has addressed this vulnerability with CVS
revision 1.20 of iso.c. For more information, visit the following URL.
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2008-1801 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org/), which standardizes names for
VIII. DISCLOSURE TIMELINE
11/12/2007 Initial vendor notification
11/19/2007 Initial vendor response
05/07/2008 Public disclosure
The discoverer of this vulnerability wishes to remain anonymous.
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