Fortinet FortiClient VPN Credential Disclosure

2017.12.14
Credit: SEC
Risk: Medium
Local: Yes
Remote: No
CWE: CWE-200


CVSS Base Score: 4/10
Impact Subscore: 2.9/10
Exploitability Subscore: 8/10
Exploit range: Remote
Attack complexity: Low
Authentication: Single time
Confidentiality impact: Partial
Integrity impact: None
Availability impact: None

SEC Consult Vulnerability Lab Security Advisory < 20171213-0 > ======================================================================= title: VPN credentials disclosure product: Fortinet FortiClient vulnerable version: <4.4.2335 on Linux, <5.6.1 on Windows, <5.6.1 on Mac OSX fixed version: 4.4.2335 on Linux, 5.6.1 on Windows, 5.6.1 on Mac OS X CVE number: CVE-2017-14184 impact: High homepage: https://www.fortinet.com/ | http://forticlient.com/ found: 2017-08-29 by: M. Li (Office Singapore) SEC Consult Vulnerability Lab An integrated part of SEC Consult Bangkok - Berlin - Linz - Luxembourg - Montreal - Moscow Kuala Lumpur - Singapore - Vienna (HQ) - Vilnius - Zurich https://www.sec-consult.com ======================================================================= Vendor description: ------------------- "From the start, the Fortinet vision has been to deliver broad, truly integrated, high-performance security across the IT infrastructure. We provide top-rated network and content security, as well as secure access products that share intelligence and work together to form a cooperative fabric. Our unique security fabric combines Security Processors, an intuitive operating system, and applied threat intelligence to give you proven security, exceptional performance, and better visibility and control--while providing easier administration." Source: https://www.fortinet.com/corporate/about-us/about-us.html Business recommendation: ------------------------ The patched FortiClient versions should be installed immediately as the VPN credentials could be decrypted by an attacker. Vulnerability overview/description: ----------------------------------- FortiClient stores the VPN authentication credentials in a configuration file (on Linux or Mac OSX) or in registry (on Windows). The credentials are encyrpted but can still be recovered since the decryption key is hardcoded in the program and the same on all installations. Above all, the aforementioned storage is world readable, which actually lays the foundation for the credential recovery. Proof of concept: ----------------- 1) Hardcoded key The hardcoded key can be disclosed on the Linux version by issuing the following command: $ strings forticlientsslvpn |grep "fc_1A" fc_1A2Brown3Fox4Jumped5Over6A7Lazy8Dog The same decryption key can be found in the Windows and Mac OSX binary. 2) Overly permissive access control The read access of the configuration file is set for "others" too, making the file world-readable. On Mac OSX, the file can be found under /Library/Application Support/Fortinet/FortiClient/conf/vpn.plist while the same dataset is stored in the registry key HKLM\SOFTWARE\WOW6432Node\Fortinet\FortiClient\Sslvpn\Tunnels on Windows, which is world-readable for all users as well. $ ls -l /home/user/.fctsslvpnhistory -rw-rw-rw- 1 root root 1227 Aug 23 12:26 .fctsslvpnhistory $ cat /home/user/.fctsslvpnhistory ... profile=demo p12passwdenc=Enc 420d2ee65abded897a69c50f4995397969f1c1f949055d8e51 path= passwordenc=Enc 420d2ee65abded897a69c50f49956909f61e3e549873cdfecf12bafdfa7b78f789a17ba1a5a6c9eb1803 user=li port=443 server=server.com ... Combining the two issues, an attacker can steal the password of any user who has a FortiClient profile on the system. In an enterprise environment, where employees usually log onto VPN server with their domain credentials, a vicious employee can extensively harvest the credentials of colleagues by logging onto the workstation where the credentials have been stored. Hence an attacker might steal credentials of any user in the domain and gain access to their user account (e.g. emails, other private data). SEC Consult developed a proof of concept tool which takes as input the encrypted string, and prints the decrypted hexdecimal bytes followed by the recovered password. For now, this tool will not be released to give users more time to patch. $ kr 420d2ee65abded897a69c50f49956909f61e3e549873cdfecf12bafdfa7b78f789a17ba1a5a6c9eb1803 0x50 0x61 0x73 0x73 0x77 0x6f 0x72 0x64 0x52 0x65 0x63 0x6f 0x76 0x65 0x72 0x65 0x64 0x00 PasswordRecovered The advisory on our website also contains further detailed technical information with screenshots: https://www.sec-consult.com/en/blog/advisories/vpn-credentials-disclosure-in-fortinet-forticlient/index.html Vulnerable / tested versions: ----------------------------- The vulnerabilities have been identified in version 4.4.2332 on Linux, version 5.6.0.1075 on Windows as well as version 5.6.0.703 on Mac OSX, which were the latest version of the product at the audit time to our best knowledge. Vendor contact timeline: ------------------------ 2017-08-30: Contacting vendor through psirt@fortinet.com 2017-09-19: Contacting vendor again due to lost message 2017-09-20: Vendor confirmed and assigned CVE-2017-14184 to the issues 2017-10-19: Vendor requested to postpone the release date 2017-11-02: Vendor informed the fix for Windows and OS X was done 2017-11-22/23: Vendor released 5.6.1 for OS X and 5.6.2 for Windows 2017-12-08: Vendor informed that the fix for Linux is available together with FortiOS release version 5.4.7 2017-12-13: Public disclosure of advisory Solution: --------- According to the vendor, all the identified issues have been fixed in the following versions: * FortiClient for Windows v5.6.1 * FortiClient for Mac OSX v5.6.1 * FortiClient SSLVPN Client for Linux v4.4.2335 released together with FortiOS 5.4.7 For further information see the website of the vendor: https://fortiguard.com/psirt/FG-IR-17-214 Please upgrade to the latest version immediately. Workaround: ----------- It is recommended not to save the password and remove "read/write" permissions for low privileged users or groups. Advisory URL: ------------- https://www.sec-consult.com/en/vulnerability-lab/advisories/index.html ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SEC Consult Vulnerability Lab SEC Consult Bangkok - Berlin - Linz - Luxembourg - Montreal - Moscow Kuala Lumpur - Singapore - Vienna (HQ) - Vilnius - Zurich About SEC Consult Vulnerability Lab The SEC Consult Vulnerability Lab is an integrated part of SEC Consult. It ensures the continued knowledge gain of SEC Consult in the field of network and application security to stay ahead of the attacker. The SEC Consult Vulnerability Lab supports high-quality penetration testing and the evaluation of new offensive and defensive technologies for our customers. Hence our customers obtain the most current information about vulnerabilities and valid recommendation about the risk profile of new technologies. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Interested to work with the experts of SEC Consult? Send us your application https://www.sec-consult.com/en/career/index.html Interested in improving your cyber security with the experts of SEC Consult? Contact our local offices https://www.sec-consult.com/en/contact/index.html ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Mail: research at sec-consult dot com Web: https://www.sec-consult.com Blog: http://blog.sec-consult.com Twitter: https://twitter.com/sec_consult EOF M. Li / @2017


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