From labs-no-reply@idefense.com Wed Mar 2 14:00:32 2005 From: iDEFENSE Labs To: bugtraq@securityfocus.com, vulnwatch@vulnwatch.org Date: Wed, 2 Mar 2005 10:53:13 -0500 Subject: iDEFENSE Security Advisory 03.02.05: Computer Associates License Client/Server GCR Checksum Buffer Overflow Computer Associates License Client/Server GCR Checksum Buffer Overflow iDEFENSE Security Advisory 03.02.05 www.idefense.com/application/poi/display?id=215&type=vulnerabilities March 2, 2005 I. BACKGROUND The Computer Associates License Client/Server applications provide a method for CA products to register their licenses on the network. The License Client and Server are distributed with almost all CA software distributions. More information about Computer Associates software products is available from: http://www3.ca.com/Products/ II. DESCRIPTION Remote exploitation of a buffer overflow vulnerability in Computer Associates License Server and License Client can allow attackers to execute arbitrary code. The vulnerability specifically exists due to insufficient bounds checking on user-supplied values in GCR requests. The GCR request packet format is shown below: A0 GCR HOSTNAMEHARDWARE<001122334455>LOCALE IDENT1IDENT2IDENT3IDENT4 OSOLFFILE<0 0 0>SERVERVERSION<3 1.54.0> NETWORK<127.0.0.1 HOSTNAME 255.255.255.0>MACHINE CHECKSUMS<1 2 3 4 5 6 7 8 9 10 11 12>RMTV<1.00> If the second, fifth, eighth, or eleventh field of the Checksums item contains a large string, a stack overflow will occur. The format specifier for the call to sscanf() is simply: "%x %s %i %x %s %i %x %s %i %x %s %i" If the eleventh field is used to overflow the local stack buffer, the return address will be overwritten with the address at 64 bytes into the overflow string. Ollydbg output after SEH overwrite in CA License Client: EAX 00630510 ECX 7C91056D ntdll.7C91056D EDX 003B0000 EBX 00D4E053 ASCII "GCR" ESP 0082FC10 ASCII "XXXXXXXXXXXXXXXXXXXXXXXXXXXXX EBP 00D4E050 ASCII "A0" ESI 0082FCBC ASCII "XXXXXXXXXXXXXXXXXXXXXXXXXXXXX EDI 00D4E057 ASCII "HOSTNAMEHARDWARE<0011 EIP DEADC0DE Log data, item 0 Address=DEADC0DE Message=Access violation when executing [DEADC0DE] III. ANALYSIS Exploitation allows remote attackers to execute arbitrary code under the privileges of Local System. A GETCONFIG packet exchange which discloses the remote operating system version usually proceeds the GCR request and increases the likelihood of successful exploitation. The CA License Server does not run by default, but is packaged with most Computer Associates software distributions. The CA License Client does run by default and is packaged with almost all Computer Associates software. IV. DETECTION iDEFENSE has confirmed that CA License Server 0.1.0.15 and CA License Client 0.1.0.15 are vulnerable. V. WORKAROUND Use a firewall to only allow trusted hosts to connect to the Computer Associates License Server and Client ports. VI. VENDOR RESPONSE A vendor advisory for this issue is available at: http://supportconnectw.ca.com/public/ca_common_docs/security_notice.asp Patches for this issue are available at: http://supportconnectw.ca.com/public/reglic/downloads/licensepatch.asp#a lp VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CAN-2005-0581 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org), which standardizes names for security problems. This is one of several overflows that have been assigned CAN-2005-0581. VIII. DISCLOSURE TIMELINE 12/01/2004 Initial vendor notification 12/01/2004 Initial vendor response 03/02/2005 Coordinated public disclosure IX. CREDIT An anonymous contributor is credited with discovering this vulnerability. Get paid for vulnerability research http://www.idefense.com/poi/teams/vcp.jsp Free tools, research and upcoming events http://labs.idefense.com X. LEGAL NOTICES Copyright (c) 2005 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.