Apple Darwin Streaming Proxy Multiple Vulnerabilities

iDefense Security Advisory 05.10.07
http://labs.idefense.com/intelligence/vulnerabilities/
May 10, 2007

I. BACKGROUND

Darwin Streaming Server is a server technology that facilitates
streaming of QuickTime data to clients across the Internet using the
industry standard RTP and RTSP protocols.

The Darwin Streaming Proxy is an application-specific proxy which would
normally be run in a border zone or perimeter network. It is used to
give client machines, within a protected network, access to streaming
servers where the firewall blocks RTSP connections or RTP/UDP data
flow. For more information, please visit the product website at via
following URL.

http://developer.apple.com/opensource/server/streaming/index.html

II. DESCRIPTION

Remote exploitation of multiple buffer overflow vulnerabilities in Apple
Inc.'s Darwin Streaming Proxy allows attackers to execute arbitrary code
with the privileges of running service, usually root.

Due to insufficient sanity checking, a stack-based buffer overflow could
occur while trying to extract commands from the request buffer. The
"is_command" function, located in proxy.c, lacks bounds checking when
filling the 'cmd' and 'server' buffers.

Additionally, a heap-based buffer overflow could occur while processing
the "trackID" values contained within a "SETUP" request. If a request
with more than 32 values is encountered, memory corruption will occur.

III. ANALYSIS

Successful exploitation allows remote attackers to execute arbitrary
code with the privileges of the running service, usually root.

No credentials are required for accessing the vulnerable code.

The stack-based buffer overflow vulnerability relies on compiler
optimizations. iDefense has verified the Darwin Streaming Proxy 4.1
binary release for Fedora Core is not vulnerable. The binary produced
from a out-of-the-box compile on Fedora was confirmed vulnerable.

IV. DETECTION

iDefense has confirmed the existence of these vulnerabilities in Darwin
Streaming Server 5.5.4 and Darwin Streaming Proxy 4.1. It is suspected
that earlier versions are also vulnerable.

V. WORKAROUND

Employ firewalls, access control lists or other TCP/UDP restriction
mechanisms to limit access to vulnerable systems and services.

VI. VENDOR RESPONSE

Apple has addressed this vulnerability by releasing version
5.5.5 of Darwin Streaming Server. More information can be found from
Apple's Security Update page or the Darwin Streaming Server advisory
page at the respective URLs below.

http://docs.info.apple.com/article.html?artnum=61798
http://docs.info.apple.com/article.html?artnum=305495

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name
CVE-2007-0748 to the heap-based buffer overflow and CVE-2007-0749 to
stack-based
buffer overflow. These names are a candidate for inclusion in the CVE list
(http://cve.mitre.org/), which standardizes names for security problems.

VIII. DISCLOSURE TIMELINE

04/09/2007  Initial vendor notification
04/09/2007  Initial vendor response
05/10/2007  Coordinated public disclosure

IX. CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

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X. LEGAL NOTICES

Copyright © 2007 iDefense, Inc.

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at the time of publishing based on currently available information. Use
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