===================================================================== CERT-Renater Note d'Information No. 2007/VULN291 _____________________________________________________________________ DATE : 12/07/2007 HARDWARE PLATFORM(S) : / OPERATING SYSTEM(S) : Windows et Unix avec SquirrelMail ====================================================================== SquirrelMail G/PGP Plugin deleteKey() Command Injection Vulnerability iDefense Security Advisory 07.11.07 http://labs.idefense.com/intelligence/vulnerabilities/ Jul 11, 2007 I. BACKGROUND The SquirrelMail G/PGP Encrpytion Plugin is a general purpose encryption, decryption, and digital signature plug-in for SquirrelMail that implements the OpenPGP standard using GPG. More information is available at the following URL. http://www.squirrelmail.org/plugin_view.php?id=153 II. DESCRIPTION Remote exploitation of a command injection vulnerability in the G/PGP Encrpytion Plugin for The SquirrelMail Project Team's SquirrelMail webmail package allows attackers to execute arbitrary commands with the privileges of the underlying web server. The problem specifically exists within the function deleteKey() defined in gpg_keyring.php. A call is made to exec() with unfiltered user-supplied data as demonstrated in the following piece of code: $command = "$path_to_gpg --batch --no-tty --yes --homedir \ $gpg_key_dir $flag $fpr 2>&1"; exec($command, $output, $returnval); The deleteKey() routine is called from three files: import_key_file.php, import_key_text.php and keyring_main.php. the '$fpr' variable from above is supplied in the POST data. The attacker must have a valid authenticated session to exploit this vulnerability. III. ANALYSIS Exploitation of the described vulnerability allows authenticated remote attackers to execute arbitrary commands with the privileges of the underlying web server. This vulnerability could be exploited by webmail users to gain shell access on the target server and potentially further compromise the system with local privilege escalation vulnerabilities. IV. DETECTION iDefense has confirmed the existence of this vulnerability in the latest version of the G/PGP Encryption Plugin for SquirrelMail, version 2.1. Furthermore, this vulnerability has been confirmed to exist as early as version 2.0. Other versions may be affected. V. WORKAROUND Disable the G/PGP Plugin if it is not required. Alternatively, add the following line above the initialization of the '$command' variable just prior to the call to exec(): $fpr = escapeshellarg($fpr); Please note that this is an unofficial source patch, but should be sufficient as a workaround until an official patch is released from the vendor. VI. VENDOR RESPONSE The maintainers of the SquirrelMail G/PGP plug-in have not responded to repeated inquires regarding this vulnerability. As such, it remains unpatched, even in the most current release made on July 7th, 2007. VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2005-1924 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org/), which standardizes names for security problems. VIII. DISCLOSURE TIMELINE 10/27/2005 Initial vendor notification 10/27/2005 Initial vendor response 03/02/2006 Second vendor notification 02/16/2007 Third vendor notification 07/11/2007 Public disclosure IX. CREDIT The discoverer of this vulnerability wishes to remain anonymous. Get paid for vulnerability research http://labs.idefense.com/methodology/vulnerability/vcp.php Free tools, research and upcoming events http://labs.idefense.com/ X. LEGAL NOTICES Copyright © 2007 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 e-mail 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. ============================================================================= SquirrelMail G/PGP Plugin gpg_check_sign_pgp_mime() Command Injection Vulnerability iDefense Security Advisory 07.11.07 http://labs.idefense.com/intelligence/vulnerabilities/ Jul 11, 2007 I. BACKGROUND The SquirrelMail G/PGP Encrpytion Plugin is a general purpose encryption, decryption, and digital signature plug-in for SquirrelMail that implements the OpenPGP standard using GPG. More information is available at the following URL. http://www.squirrelmail.org/plugin_view.php?id=153 II. DESCRIPTION Remote exploitation of a command injection vulnerability in the G/PGP Encrpytion Plugin for The SquirrelMail Project Team's SquirrelMail webmail package allows attackers to execute arbitrary commands with the privileges of the underlying web server. The problem specifically exists within the function gpg_check_sign_pgp_mime() defined in gpg_hook_functions.php. A call is made to exec() with unfiltered user-supplied data as demonstrated in the following piece of code: $command = "echo -n \"$messageSignedText\" | $path_to_gpg --batch \ --no-tty --homedir $gpg_key_dir --verify ".\ $detachedSignatureFilename."- 2>&1"; if ($debug) echo "gpg command: ".$command."\"; exec($command, $results, $returnval); The '$messageSignedText' variable from above contains the stripped e-mail message. III. ANALYSIS Exploitation of the described vulnerability allows unauthenticated remote attackers to execute arbitrary commands with the privileges of the underlying web server. Exploitation of this vulnerability occurs when a target webmail user opens a malicious e-mail message. As such the vulnerability can be exploited by any attacker who can convince a target user to open a malicious message. IV. DETECTION iDefense has confirmed the existence of this vulnerability in version 2.0 of the G/PGP Encryption Plugin for SquirrelMail. It is suspected that earlier versions of the plug-in are also affected. V. WORKAROUND Disable the G/PGP Plugin if it is not required. Alternatively, add the following line above the initialization of the '$command' variable just prior to the call to exec(): $messageSignedText= escapeshellarg($messageSignedText); Please note that this is an unofficial source patch, but should be sufficient as a workaround. VI. VENDOR RESPONSE The maintainers of the SquirrelMail G/PGP plug-in have not responded to repeated inquires regarding this vulnerability. Versions since 2.1devbuild12Sep06 appear to include a fix for this problem. This problem is not present in the recent 2.1 release made on July 7th, 2007. VII. CVE INFORMATION A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not been assigned yet. VIII. DISCLOSURE TIMELINE 10/27/2005 Initial vendor notification 10/27/2005 Initial vendor response 03/02/2006 Second vendor notification 02/16/2007 Third vendor notification 07/11/2007 Public disclosure IX. CREDIT The discoverer of this vulnerability wishes to remain anonymous. Get paid for vulnerability research http://labs.idefense.com/methodology/vulnerability/vcp.php Free tools, research and upcoming events http://labs.idefense.com/ X. LEGAL NOTICES Copyright © 2007 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 e-mail 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. ============================================================================ SquirrelMail G/PGP Plugin gpg_recv_key() Command Injection Vulnerability iDefense Security Advisory 07.11.07 http://labs.idefense.com/intelligence/vulnerabilities/ Jul 11, 2007 I. BACKGROUND The SquirrelMail G/PGP Encrpytion Plugin is a general purpose encryption, decryption, and digital signature plug-in for SquirrelMail that implements the OpenPGP standard using GPG. More information is available at the following URL. http://www.squirrelmail.org/plugin_view.php?id=153 II. DESCRIPTION Remote exploitation of a command injection vulnerability in the G/PGP Encrpytion Plugin for The SquirrelMail Project Team's SquirrelMail webmail package allows attackers to execute arbitrary commands with the privileges of the underlying web server. The problem specifically exists within the function gpg_recv_key() defined in gpg_key_functions.php. A call is made to exec() with unfiltered user-supplied data as demonstrated in the following piece of code: $command = "$path_to_gpg --batch --no-tty --homedir $gpg_key_dir \ --keyserver hkp://$keyserver --recv-key $searchkeyid 2>&1"; [...] exec($command, $output, $returnval); The aforementioned '$keyserver' variable is supplied in the POST data to the gpg_options.php script. The attacker must have a valid authenticated session to exploit this vulnerability. III. ANALYSIS Exploitation of the described vulnerability allows authenticated remote attackers to execute arbitrary commands with the privileges of the underlying web server. This vulnerability could be exploited by webmail users to gain shell access on the target server and potentially further compromise the system with local privilege escalation vulnerabilities. IV. DETECTION iDefense has confirmed the existence of this vulnerability in the latest version of the G/PGP Encryption Plugin for SquirrelMail, version 2.1. Furthermore, this vulnerability has been confirmed to exist as early as version 2.0. Other versions may be affected. V. WORKAROUND Disable the G/PGP Plugin if it is not required. Alternatively, add the following line above the initialization of the '$command' variable just prior to the call to exec(): $keyserver = escapeshellarg($keyserver); Please note that this is an unofficial source patch, but should be sufficient as a workaround until an official patch is released from the vendor. VI. VENDOR RESPONSE The maintainers of the SquirrelMail G/PGP plug-in have not responded to repeated inquires regarding this vulnerability. As such, it remains unpatched, even in the most current release made on July 7th, 2007. VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2005-1924 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org/), which standardizes names for security problems. VIII. DISCLOSURE TIMELINE 10/27/2005 Initial vendor notification 10/27/2005 Initial vendor response 03/02/2006 Second vendor notification 02/16/2007 Third vendor notification 07/11/2007 Public disclosure IX. CREDIT The discoverer of this vulnerability wishes to remain anonymous. Get paid for vulnerability research http://labs.idefense.com/methodology/vulnerability/vcp.php Free tools, research and upcoming events http://labs.idefense.com/ X. LEGAL NOTICES Copyright © 2007 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 e-mail 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. ============================================================================ SquirrelMail G/PGP Plugin gpg_help.php Local File Inclusion Vulnerability iDefense Security Advisory 07.11.07 http://labs.idefense.com/intelligence/vulnerabilities/ Jul 11, 2007 I. BACKGROUND The SquirrelMail G/PGP Encrpytion Plugin is a general purpose encryption, decryption, and digital signature plug-in for SquirrelMail that implements the OpenPGP standard using GPG. More information is available at the following URL. http://www.squirrelmail.org/plugin_view.php?id=153 II. DESCRIPTION Remote exploitation of a local file inclusion vulnerability in version 2.0 of the SquirrelMail G/PGP Plugin could allow an authenticated webmail user to execute arbitrary PHP code under the security context of the running web server. Version 2.0 of the SquirrelMail G/PGP Plugin contains an implementation flaw in the way it includes certain files. Specifically, the 'gpg_help.php' and 'gpg_help_base.php' files will include local files that are supplied via the 'help' HTTP GET request parameter. An excerpt from the code follows: 68 // Help body text is inserted here via GET parameter 69 require_once (SM_PATH.'plugins/gpg/help/' . $_GET['help'] ); By using directory traversal specifiers, an attacker can trivially cause files stored on the Web server to be parsed as PHP code. III. ANALYSIS Exploitation could allow an attacker to include an arbitrary local file on the affected host. Due to the lack of input validation on $GET_['help'], directory traversal specifiers could be utilized to parse any file on the system as PHP code. IV. DETECTION iDefense has confirmed the existence of this vulnerability in version 2.0 of the G/PGP Encryption Plugin for SquirrelMail. It is suspected that earlier versions of the plug-in are also affected. V. WORKAROUND iDefense is unaware of any available workarounds for this vulnerability. VI. VENDOR RESPONSE The maintainers of the SquirrelMail G/PGP plug-in have not responded to repeated inquires regarding this vulnerability. Versions since gpg.2.1devbuild14Jun07 appear to include a fix for this problem. This problem is not present in the recent 2.1 release made on July 7th, 2007. VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2006-4169 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org/), which standardizes names for security problems. VIII. DISCLOSURE TIMELINE 08/16/2006 Initial vendor notification 10/06/2006 Second vendor notification 02/16/2007 Third vendor notification 07/11/2007 Public disclosure IX. CREDIT The discoverer of this vulnerability wishes to remain anonymous. Get paid for vulnerability research http://labs.idefense.com/methodology/vulnerability/vcp.php Free tools, research and upcoming events http://labs.idefense.com/ X. LEGAL NOTICES Copyright © 2007 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 e-mail 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. ====================================================================== ========================================================= Les serveurs de référence du CERT-Renater http://www.urec.fr/securite http://www.cru.fr/securite http://www.renater.fr ========================================================= + CERT-RENATER | tel : 01-53-94-20-44 + + 151 bd de l'Hopital | fax : 01-53-94-20-41 + + 75013 Paris | email: certsvp@renater.fr + =========================================================