AUSCERT External Security Bulletin Redistribution

                 ESB-2003.0122 -- @stake Security Advisory
 QuickTime/Darwin Streaming Administration Server Multiple vulnerabilities
                             26 February 2003


        AusCERT Security Bulletin Summary

Product:                Darwin Streaming Server 4.1.2
                        QuickTime Streaming Server 4.1.1
Vendor:                 @stake, Inc.
Operating System:       Mac OS X
Impact:                 Increased Privileges
                        Execute Arbitrary Code/Commands
                        Read-only Data Access
                        Provide Misleading Information
Access Required:        Existing Account

Comment: CVE Id: CAN-2003-0050, CAN-2003-0051, CAN-2003-0052,
                 CAN-2003-0053, CAN-2003-0054, CAN-2003-0055

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Hash: SHA1

                               @stake, Inc.

                            Security Advisory

Advisory Name: QuickTime/Darwin Streaming Administration
               Server Multiple vulnerabilities
 Release Date: 03-24-2003
  Application: Darwin Streaming Server 4.1.2
               QuickTime Streaming Server 4.1.1
     Platform: MacOS X, Linux, Solaris, Windows
     Severity: Remote Command Execution / Privilege Escalation
               Arbitrary Directory Listings / Cross Site
               Scripting x2
               Physical Path Revelation / Buffer Overflow
      Authors: Dave G. <daveg@atstake.com>
               Ollie Whitehouse <ollie@atstake.com>
Vendor Status: Vendor has software update
CVE Candidate: CAN-2003-0050,51,52,53,54,55
    Reference: www.atstake.com/research/advisories/2003/a032403-1.txt

Apple Darwin and QuickTime Streaming Administration Servers are web
based services that allow administrators to manage the Darwin and
QuickTime Streaming Servers. By default, these servers run as root on
port 1220/tcp.

There is a remote pre-authentication remote command execution
condition within this service.  Any attacker with a web browser and
access to the service can execute commands on the underlying
operating system.  Certain versions of the Darwin Streaming
Administration Server restrict this attack, allowing an attacker to
execute a command, but without additional command line arguments.

Additionally, a number of other vulnerabilities can be used to:

a) Reveal the physical path
b) Retrieve arbitrary directory listings outside of the web root
c) Initiate cross-site scripting attacks
d) Local privilege escalation through a buffer overflow


1) Arbitrary Command Execution

The Darwin Streaming Administration Server relies on the
parse_xml.cgi application to authenticate and interface with the
user.  This CGI is written in PERL and passes unvalidated input to
the open() function. The open() function will execute commands when
the pipe '|' characters are inserted into the input.

The call in question takes input from a parameter passed in
through a GET request to the CGI.  The QuickTime Streaming Server is
vulnerable to this attack.  Newer versions of the Darwin
Administration Server added a check to determine the existence of the
template file  (the -e function).  While this check does provide
protection, there is a well known technique to partially bypass(*)
it. By inserting a NULL (0x00) between the last character of the
command and the pipe, an attacker can pass the file existence check,
and execute a command. 
This request will pass the file existence check.  However, attackers
cannot add additional command line parameters.  While this does limit
the ability of the attacker to take full control of the operating
system, there are several situations where this vulnerability still
presents a risk:

a) If an attacker can create arbitrary files and know its location.
b) If an attacker has a non-root account on the system, this
  vulnerability can be used to obtain root privileges.
c) If an attacker can find an application on the system that can
  reduce the security or availability of the system without
  requiring additional command line arguments.

(*) "PERL CGI problems", Phrack 55, Article 7, rain.forest.puppy

2) Physical Path Revelation

In addition it is possible to cause the same CGI application to
revealthe physical path which the Darwin/QuickTime admin servers are
installed within by passing a NULL as the filename parameter.

3) Arbitrary Directory Listings

Parse_xml.cgi is also susceptible to arbitrary directory listings due
to the lack of user input validation within the application.  It is
possible for an attacker to use the open() function to open the inode
of a directory as a file under UNIX operating systems to retrieve a
directory listing. Although it should be noted that to view the
output correctly in a web browser it may be required to view the
source code to the page in order to see the output returned.

4) Cross Site Scripting

There is a minor security vulnerability in the way that parse_xml.cgi
generates error messages when a filename which does not exist is
passed as the 'filename' parameter. This potentially opens the
administrators to the possibility of a cross site scripting attack.

This combined with the fact that the 'qtpassword' cookie is the
administrative username and password Base64 encoded provides an easy
method of gaining valid credentials to the site in question.

5) Cross Site Scripting - Round 2

There exists another cross site scripting issue which is more likely
to be exploited due to the manner by which it occurs. If an
unauthenticated user makes a request to port 7070, they can supply
scripting code as part of the argument to the rtsp DESCRIBE method.

This request is then written to the log file. When the logs are
viewed within the administrative interface, the code will execute in
the administrator's browser session.

6) Buffer Overflow in MP3 Broadcasting Module

There is a buffer overflow in the MP3 broadcasting module contained
within the streaming server. If you have an MP3 file which has
filename of over 256 bytes then a buffer overflow will occur.

Due to the fact that the streaming server by default runs as root
(on Unix) means that potentially it can be used by local/ftp users to
escalate privileges.

Vendor Response:

Apple has an update for Mac OS X Server which addresses these

The software update is available from the following locations:

  Updating from Mac OS X Server 10.2.3:

  Updating from Mac OS X Server 10.2, 10.2.1, or 10.2.2:


You should apply the software update available from Apple.  If this
is not possible it is recommended that this service not be Internet


Dave G. <daveg@atstake.com> is responsible for finding issue #1:
Arbitrary Command Execution.

Ollie Whitehouse <ollie@atstake.com> is responsible for finding
issues #2: Physical Path Revelation, #3: Arbitrary Directory
Listings, #4: Cross Site Scripting, #5 Cross Site Scripting -
Round 2, and #6 Buffer Overflow in MP3 brodcasting module.

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.

 CAN-2003-0050 Arbitrary command execution in QuickTime Streaming
 CAN-2003-0051 Physical path revelation in QuickTime Streaming
 CAN-2003-0052 Directory listings in QuickTime Streaming Server
 CAN-2003-0053 Login credentials in QuickTime Streaming Server
 CAN-2003-0054 Arbitrary command execution when viewing QTSS logs
 CAN-2003-0055 Buffer overflow in MP3 Broadcasting application

@stake Vulnerability Reporting Policy:

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

PGP Key:

Copyright 2003 @stake, Inc. All rights reserved

Version: PGP 8.0 - not licensed for commercial use: www.pgp.com


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