Rebootuser | Tag Archives: escalation

Tag Archives: escalation

LinEnum Overhaul!

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Well it’s been a while, but the latest (0.5 experimental) release of LinEnum is now available.

A few more scans have been added, which include password policy checks, reading of the umask setting and checking the ownership of binaries associated with inetd.conf (and variants). There will be plenty more additions in this area in the *very* near future.

However, the biggest changes have been made in the functionality of the script. The reporting functionality has been altered so it should work on legacy systems (although, admittedly ‘tee’ is a dependency). Additionally, by default, the script now runs just basic/quick checks. A ‘thorough’ tests switch (-t) has been added, which allows the user to choose if they wish to run lengthy scans (such as file permission checks, SUID/GUID file searches and so on).

The biggest addition is the introduction of ‘export’ functionality (experimental stages). If a scan is run with this switch (-e) all ‘interesting’ files (/etc/password, user history, SSH files etc.) will be copied to a location of the users choosing. Essentially these files, along with the LinEnum report (-r), should allow for easier offline analysis.

A quick peek at the help menu highlights the changes/additions:

linenum05

The Github repository has been updated with this latest addition and is available from here.

A more detailed version of the changelog can be found here and the associated ‘readme’ file here.

If you have any suggestions/improvements/criticisms re LinEnm please do contact me and I’ll try to address these in the next release – otherwise please feel free to contribute to the project!

Introducing LinEnum – Scripted Local Linux Enumeration & Privilege Escalation Checks

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LinEnum will automate many of the checks that I’ve documented in the Local Linux Enumeration & Privilege Escalation Cheatsheet. It’s a very basic shell script that performs over 65 checks, getting anything from kernel information to locating possible escalation points such as potentially useful SUID/GUID files and Sudo/rhost mis-configurations and more.

An additional ‘extra’ feature is that the script will also use a provided keyword to search through *.conf and *.log files. Any matches will be displayed along with the full file path and line number on which the keyword was identified.

linenum

After the scan has completed (please be aware that it make take some time) you’ll be presented with (possibly quite extensive) output, to which any key findings will be highlighted in yellow with everything else documented under the relevant headings.

Example output is shown in the following screenshot:

linenum-out-example-001

I’m afraid from hereon in it’s a manual task to check over the results.

Below is a high-level summary of the checks/tasks performed by LinEnum:

  • Kernel and distribution release details
  • System Information:
    • Hostname
    • Networking details:
      • Current IP
      • Default route details
      • DNS server information
  • User Information:
    • Current user details
    • Last logged on users
    • Llist all users including uid/gid information
    • List root accounts
    • Extract full details for ‘default’ uid’s such as 0, 1000, 1001 etc
    • Attempt to read restricted files i.e. /etc/shadow
    • List current users history files (i.e .bash_history, .nano_history etc.)
  • Privileged access:
    • Determine if /etc/sudoers is accessible
    • Determine if the current user has Sudo access without a password
    • Are known ‘good’ breakout binaries available via Sudo (i.e. nmap, vim etc.)
    • Is root’s home directory accessible
    • List permissions for /home/
  • Environmental:
    • Display current $PATH
  • Jobs/Tasks:
    • List all cron jobs
    • Locate all world-writable cron jobs
    • Locate cron jobs owned by other users of the system
  • Services:
    • List network connections (TCP & UDP)
    • List running processes
    • Lookup and list process binaries and associated permissions
    • List inetd.conf/xined.conf contents and associated binary file permissions
    • List init.d binary permissions
  • Version Information (of the following):
    • Sudo
    • MYSQL
    • Postgres
    • Apache
  • Default/Weak Credentials:
    • Checks for default/weak Postgres accounts
    • Checks for default root/root access to local MYSQL services
  • Searches:
    • Locate all SUID/GUID files
    • Locate all world-writable SUID/GUID files
    • Locate all SUID/GUID files owned by root
    • Locate ‘interesting’ SUID/GUID files (i.e. nmap, vim etc)
    • List all world-writable files
    • Find/list all accessible *.plan files and display contents
    • Find/list all accesible *.rhosts files and display contents
    • Show NFS server details
    • Locate *.conf and *.log files containing keyword supplied at script runtime
    • List all *.conf files located in /etc
    • Locate mail

Some of the above commands are privileged/and or the related task may be nonexistent and will therefore most likely fail. The user shouldn’t be alerted to failed results, just the output from successful commands should be displayed.

To date I’ve tested LinEnum on Ubuntu, Debian, Redhat and CentOS. If you feel that there are some additional checks that you’d like to see added to the script and/or you find any bugs etc. please post within the below comments section (or feel free to contribute towards the project).

Please note that I realise that my scripting ability is limited and there may well be better/easier/quicker ways of performing some of the tasks. However, all that said, hopefully you’ll find this a useful tool.

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LinEnum can be downloaded from Github

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Finally, I’d like to say thanks to @pentestmonkey for his inspirational unix-privesc-check tool that I’ll continue to use on a very regular basis!