Apple Darwin Streaming Server DESCRIBE Null Byte Denial of Service Vulnerability iDEFENSE Security Advisory 12.03.2004 www.idefense.com/application/poi/display?id=159&type=vulnerabilities December 03, 2004 I. BACKGROUND Darwin Streaming Server is an open source version of Apple's QuickTime Streaming Server technology that allows you to send streaming media to clients across the Internet using the industry standard RTP and RTSP protocols. II. DESCRIPTION Remote exploitation of an input validation vulnerability in Apple Computer Inc.'s Darwin Streaming Server allows attackers to cause a denial of service condition. The vulnerability specifically occurs due to insufficient sanity checking on arguments to DESCRIBE requests. A remote attacker can send a request for a location containing a null byte to cause a denial of service condition resulting in the following backtrace: Program received signal SIGSEGV, Segmentation fault. [Switching to Thread 1026 (LWP 9648)] 0x4207ac9e in chunk_free () from /lib/i686/libc.so.6 (gdb) bt #0 0x4207ac9e in chunk_free () from /lib/i686/libc.so.6 #1 0x4207ac24 in free () from /lib/i686/libc.so.6 #2 0x08096406 in FindOrCreateSession (inPath=0x408caf3c, inParams=0x81746f0, inData=0x0, isPush=0, foundSessionPtr=0x0) at APIModules/QTSSReflectorModule/QTSSReflectorModule.cpp:1262 III. ANALYSIS Successful exploitation allows any remote unauthenticated attacker to crash the targeted server, thereby preventing legitimate users from accessing streamed content. IV. DETECTION iDEFENSE has confirmed the existence of this vulnerability in Darwin Streaming Server 5.0.1. 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 systems and services. VI. VENDOR RESPONSE The following updates are available from Apple Downloads (http://www.apple.com/support/downloads//) to address this vulnerability: Mac OS X 10.2.8 Client http://www.apple.com/support/downloads//securityupdate_2004-12-02_v_1_0_ (Mac_OS_X_10_2_8_Client).html Mac OS X 10.2.8 Server http://www.apple.com/support/downloads//securityupdate_2004-12-02_v_1_0_ (Mac_OS_X_10_2_8_Server).html Mac OS X 10.3.6 Client http://www.apple.com/support/downloads//securityupdate_2004-12-02_v_1_0_ (Mac_OS_X_10_3_6_Client).html Mac OS X 10.3.6 Server http://www.apple.com/support/downloads//securityupdate_2004-12-02_v_1_0_ (Mac_OS_X_10_3_6_Server).html VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the names CAN-2004-1123 to these issues. This is a candidate for inclusion in the CVE list (http://cve.mitre.org), which standardizes names for security problems. VIII. DISCLOSURE TIMELINE 09/10/2004 Initial vendor notification 09/15/2004 Initial vendor response 12/03/2004 Coordinated public disclosure IX. CREDIT The discoverer of this vulnerability wishes to remain anonymous. Get paid for vulnerability research http://www.idefense.com/poi/teams/vcp.jsp X. LEGAL NOTICES Copyright (c) 2004 iDEFENSE, Inc. Permission is granted for the redistribution of this alert electronically. It may not be edited in any way without the express written consent of iDEFENSE. If you wish to reprint the whole or any part of this alert in any other medium other than electronically, please email customerservice@idefense.com for permission. Disclaimer: The information in the advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information. _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.netsys.com/full-disclosure-charter.html