Apache CouchDB 2.0.0 Local Privilege Escalation

`[+] Credits: John Page aka hyp3rlinx  
  
[+] Website: hyp3rlinx.altervista.org  
  
[+] Source:  
http://hyp3rlinx.altervista.org/advisories/APACHE-COUCHDB-LOCAL-PRIVILEGE-ESCALATION.txt  
  
[+] ISR: ApparitionSec  
  
  
  
Vendor:  
==================  
couchdb.apache.org  
  
  
  
Product:  
==============  
CouchDB v2.0.0  
  
Apache CouchDB is open source database software that focuses on ease of use  
and having an architecture. It has a document-oriented  
NoSQL database architecture and is implemented in the concurrency-oriented  
language Erlang; it uses JSON to store data, JavaScript  
as its query language using MapReduce, and HTTP for an API.  
  
  
Vulnerability Type:  
===================  
Privilege Escalation (Insecure File Permissions)  
  
  
  
CVE Reference:  
==============  
N/A  
  
  
  
Vulnerability Details:  
=====================  
  
CouchDB sets weak file permissions potentially allowing 'Standard' Windows  
users to elevate privileges. The "nssm.exe" (Apache CouchDB)  
executable can be replaced by a 'Standard' non administrator user, allowing  
them to add a backdoor Administrator account once the  
"Apache CouchDB" service is restarted or system rebooted.  
  
As Apache CouchDB runs as LOCALSYSTEM, standard users can now execute  
arbitrary code with the privileges of the SYSTEM.  
  
Issue is the 'C' flag (Change) for 'Authenticated Users' group.  
  
  
e.g.  
  
c:\CouchDB>cacls * | findstr Users  
  
BUILTIN\Users:(OI)(CI)(ID)R  
NT AUTHORITY\Authenticated Users:(ID)C  
NT AUTHORITY\Authenticated Users:(OI)(CI)(IO)(ID)C  
BUILTIN\Users:(OI)(CI)(ID)R  
NT AUTHORITY\Authenticated Users:(ID)C  
NT AUTHORITY\Authenticated Users:(OI)(CI)(IO)(ID)C  
BUILTIN\Users:(OI)(CI)(ID)R  
NT AUTHORITY\Authenticated Users:(ID)C  
NT AUTHORITY\Authenticated Users:(OI)(CI)(IO)(ID)C  
  
  
  
c:\CouchDB>sc qc "Apache CouchDB"  
[SC] QueryServiceConfig SUCCESS  
  
SERVICE_NAME: Apache CouchDB  
TYPE : 10 WIN32_OWN_PROCESS  
START_TYPE : 3 DEMAND_START  
ERROR_CONTROL : 1 NORMAL  
BINARY_PATH_NAME : C:\CouchDB\bin\nssm.exe  
LOAD_ORDER_GROUP :  
TAG : 0  
DISPLAY_NAME : Apache CouchDB  
DEPENDENCIES :  
SERVICE_START_NAME : LocalSystem  
  
  
  
  
Exploitation Technique:  
=======================  
Local  
  
  
  
Severity Level:  
================  
Medium  
  
  
  
  
[+] Disclaimer  
The information contained within this advisory is supplied "as-is" with no  
warranties or guarantees of fitness of use or otherwise.  
Permission is hereby granted for the redistribution of this advisory,  
provided that it is not altered except by reformatting it, and  
that due credit is given. Permission is explicitly given for insertion in  
vulnerability databases and similar, provided that due credit  
is given to the author. The author is not responsible for any misuse of the  
information contained herein and accepts no responsibility  
for any damage caused by the use or misuse of this information. The author  
prohibits any malicious use of security related information  
or exploits by the author or elsewhere.  
  
hyp3rlinx  
`