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Computer Associates License Client/Server GCR Network Buffer Overflow

03.02.05

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/

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 HOSTNAME<DEVBOX>HARDWARE<001122334455>LOCALE<English> 
IDENT1<unknown>IDENT2<unknown>IDENT3<unknown>IDENT4<unknown>
OS<Windows_NT 5.0>OLFFILE<0 0 0>SERVER<RMT>VERSION<3 1.54.0>
NETWORK<127.0.0.1 HOSTNAME 255.255.255.0>MACHINE<PC_1586_1_3201>
CHECKSUMS<1 2 3 4 5 6 7 8 9 10 11 12>RMTV<1.00><EOM>

If the IP address, hostname, or netmask contain large values, the stack
overflow can be triggered.

Ollydbg output after SEH overwrite in CA License Server:

EAX 00630210 
ECX 7C91056D ntdll.7C91056D
EDX 003B0608
EBX 00E4E053 ASCII "GCR"
ESP 00E2FC7C ASCII "XXXXXXXXXXXXXXXXXXXXXXXXXXXXX
EBP 00E4E050 ASCII "A0"
ESI 00E2FD28 ASCII "XXXXXXXXXXXXXXXXXXXXXXXXXXXXX
EDI 00E4E057 ASCII "HOSTNAME<DEVBOX>HARDWARE<0011
EIP DEADC0DE

SEH chain of thread 00000DA4, item 0 
Address=00E2FFA4
SE handler=58585858

Log data, item 0 
Address=DEADC0DE
Message=Access violation when executing [DEADC0DE]

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.

DETECTION

iDEFENSE has confirmed that CA License Server 0.1.0.15 and CA License
Client 0.1.0.15 are vulnerable.

WORKAROUND

Use a firewall to only allow trusted hosts to connect to the Computer
Associates License Server and Client ports.

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#alp

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.

DISCLOSURE TIMELINE

12/01/2004   Initial vendor notification
12/01/2004   Initial vendor response
03/02/2005   Coordinated public disclosure

CREDIT

An anonymous contributor is credited with discovering this
vulnerability.

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LEGAL NOTICES

Copyright © 2005 Verisign, 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.