Public Vulnerability Reports

CA ARCServe Backup for Laptops and Desktops Multiple Buffer Overflow Vulnerabilities

09.20.07

BACKGROUND

ARCServe Backup for Laptops and Desktops is a version of ARCServe Backup targeted at small to medium sized businesses, with many mobile/remote users. It provides client agents that detect network connectivity and commit backup data when it is found. For more information, consult the product home page at the following URL.

http://www3.ca.com/solutions/Product.aspx?ID=263

DESCRIPTION

Remote exploitation of multiple buffer overflow vulnerabilities in Computer Associates Inc.'s ARCServe Backup for Laptops and Desktops allows attackers to execute arbitrary code with SYSTEM privileges.

The LGServer contains multiple vulnerable functions that handle network requests, several of which contain more than one vulnerability. All together there are nearly 60 buffer overflows in the LGServer.

The majority of these are the result of copying remotely supplied strings into fixed-size buffers without validating that enough space is available. A list of vulnerable commands follows.

rxsAddNewUser, rxsSetUserInfo, rxsRenameUser, rxsSetMessageLogSettings, rxsExportData, rxsSetServerOptions, rxsRenameFile, rxsACIManageSend, rxsExportUser, rxsImportUser, rxsMoveUserData, rxsUseLicenseIni, rxsLicGetSiteId, rxsGetLogFileNames, rxsGetBackupLog, rxsBackupComplete, rxsSetDataProtectionSecurityData, rxsSetDefaultConfigName, rxsGetMessageLogSettings, rxsHWDiskGetTotal, rxsHWDiskGetFree, rxsGetSubDirs, rxsGetServerDBPathName, rxsSetServerOptions, rxsDeleteFile, rxsACIManageSend, rxcReadBackupSetList, rxcWriteConfigInfo, rxcSetAssetManagement, rxcWriteFileListForRestore, rxcReadSaveSetProfile, rxcInitSaveSetProfile, rxcAddSaveSetNextAppList, rxcAddSaveSetNextFilesPathList, rxcAddNextBackupSetIncWildCard, rxcGetRevisions, rxrAddMovedUser, rxrSetClientVersion

By sending requests for the above functions with specially crafted parameters, it is possible to cause a buffer overflow. Although most involve stack based buffers, several involve heap based buffers.

Additionally, a stack based buffer overflow vulnerability exists in the GetUserInfo() function. This function is a utility function that is used by many of the request handling functions. It is possible to trigger this vulnerability by passing a long user name parameter to this function.

Another stack based buffer overflow exists within the handler for the rxrLogin request. As its name suggests, this command logs in the user after reading in the name and password. This handler contains several unsafe calls to wsprintf(). By providing a long user name it is possible to overflow a fixed size stack based buffer.

ANALYSIS

Exploitation allows an attacker to execute arbitrary code with SYSTEM privileges.

In order to exploit these vulnerabilities, an attacker must be able to establish a TCP session with the LGServer on port 1900. Unsuccessful exploitation attempts will crash the server, which will not restart automatically.

All of these vulnerabilities, with the exception of those in the rxrLogin command, should only be able to be triggered by an authenticated server administrator. However, due to the authentication bypass vulnerability described in a previous iDefense advisory any unauthenticated user can trigger them.

DETECTION

iDefense has confirmed the existence of these vulnerabilities in ARCServe Backup for Laptops and Desktops version 11.1 (Build 900) for Windows. Other versions may also be affected.

WORKAROUND

iDefense is currently unaware of any workarounds for this issue.

VENDOR RESPONSE

Computer Associates has addressed these vulnerabilities with an update. For more information consult CA's security notice at the following URL.

http://supportconnectw.ca.com/public/sams/lifeguard/infodocs/caarcservebld-securitynotice.asp

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2007-5003 to the rxrLogin and GetUserInfo() issues. The remaining issues have been assigned CVE-2007-3216. These are candidates for inclusion in the CVE list (http://cve.mitre.org/), which standardizes names for security problems.

DISCLOSURE TIMELINE

03/21/2007 Initial vendor notification
03/21/2007 Initial vendor response
09/20/2007 Public disclosure

CREDIT

These vulnerabilities were discovered by an anonymous researcher and Sean Larsson of VeriSign iDefense Labs.

Get paid for vulnerability research
http://labs.idefense.com/methodology/vulnerability/vcp.php

Free tools, research and upcoming events
http://labs.idefense.com/

LEGAL NOTICES

Copyright © 2007 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 e-mail customer service 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.