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                                @stake, Inc.
                              www.atstake.com

                             Security Advisory

Advisory Name: Sustworks Unauthorized Network Monitoring and
               tcpflow format string attack
 Release Date: 08/07/2003
  Application: IPNetMonitorX and IPNetSentryX
     Platform: Mac OS X
     Severity: Local users can sniff network traffic
               Local users can become root
       Author: Dave G. <daveg@atstake.com>
Vendor Status: Fix available
CVE Candidate: CVE candidate number applied for
    Reference: www.atstake.com/research/advisories/2003/a080703-1.txt


Overview:

IPNetSentryX and IPNetMonitorX are network tools that provide
firewalling and general network monitoring respectively.  Both of
these tools come with three helper tools that each have security
issues associated with them.  The first two tools: RunTCPDump and
RunTCPFlow allow arbitrary users to monitor the network without
requiring any form of authentication or privilege.  The third tool,
tcpflow (executed by RunTCPFlow), contains a format string
vulnerability, allowing arbitrary commands to be run as the user
calling the program.  Since RunTCPFlow is setuid root and will pass
arguments to tcpflow, we can execute arbitrary commands as root.

      
Details:

RunTCPDump and RunTCPFlow are setuid root helper applications that
simply execute /usr/sbin/tcpdump and /usr/local/bin/tcpflow.  These
helper applications pass all arguments to the commands they are
executing, allowing users to execute tcpdump and tcpflow however
they choose.  Unfortunately, any user with interactive access to a
Mac OS X system with IPNetSentryX or IPNetMonitorX can run these
commands.  This allows any user on the system to be able to view
all network traffic that pass through the vulnerable system. 

For example:

bash-2.05a$ id
uid=503(dummy) gid=20(staff) groups=20(staff)
bash-2.05a$ pwd
/Applications/IPNetSentryX.app/Contents/Resources
bash-2.05a$ ./RunTCPDump -i en1 -x -v -s 4096
RunTCPDump: listening on en1
18:02:55.726143 arp who-has 192.168.0.1 tell 192.168.0.1
                         0001 0800 0604 0001 XXXX XXXX XXXX XXXX
                         0001 0000 0000 0000 c0a8 0001 0000 0000
                         0000 0000 0000 0000 0000 0000 0000


Additionally, tcpflow is vulnerable to a format string
vulnerability, which normally would not be a serious security
vulnerability.  However, since any user on a system that has
IPNetSentryX or IPNetMonitorX and tcpflow installed can cause
tcpflow to be executed as root via RunTCPFlow, an attacker can
use this vulnerability to become root.  A corresponding
@stake advisory (a080703-2) has been released on the tcpflow
format string attack.


Vendor Response:

These vulnerabilities are mitigated in the latest version of
IPNetSentryX and IPNetMonitorX available from
http://www.sustworks.com.  Mitigation strategies include
stronger input validation and access control to RunTCPDump
and RunTCPFlow.


Recommendation:

Upgrade to the latest version of IPNetSentryX and tcpflow.


Common Vulnerabilities and Exposures (CVE) Information:

The Common Vulnerabilities and Exposures (CVE) project has assigned
the following names to these issues.  These are candidates for
inclusion in the CVE list (http://cve.mitre.org), which standardizes
names for security problems.

  CVE candidate number applied for


@stake Vulnerability Reporting Policy:
http://www.atstake.com/research/policy/

@stake Advisory Archive:
http://www.atstake.com/research/advisories/

PGP Key:
http://www.atstake.com/research/pgp_key.asc

@stake is currently seeking application security experts to fill
several consulting positions.  Applicants should have strong
application development skills and be able to perform application
security design reviews, code reviews, and application penetration
testing.  Please send resumes to jobs@atstake.com.

Copyright 2003 @stake, Inc. All rights reserved.





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