Level Up! - Practical Windows Privilege Escalation
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This document provides an overview of practical Windows privilege escalation techniques. It begins with introductions and disclaimers, then discusses Windows access control models and concepts like integrity levels. It proceeds to demonstrate potential escalation avenues like exploiting privileged access elsewhere on the network, extracting credentials from files, exploiting unpatched vulnerabilities, weak permissions on services/files, AlwaysInstallElevated policies, and DLL hijacking. The document emphasizes that privilege escalation is still possible even with UAC and provides tools and references for further information.
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Level Up! - Practical Windows Privilege Escalation
- 2. C:>type disclaimer.txt •The opinions expressed in this presentation are mine and not those of my employer.
- 3. C:>whoami /all •Andrew Smith •@jakx_ •Penetration Tester •OWASP •Metasploit •CTF •Certs
- 4. C:>whois you
- 5. What are you talking about? •Relevant Windows Security Info •PrivEsc tricks win7 •Limited user -> Local Admin
- 6. Why should I care? •You wanna level up •You wanna prevent level up •Hack the planet! •You like Mario?
- 7. Why should I care? •"People designing defenses who have never had them evaluated by a good attacker is kind of like learning one of those martial arts that look more like dancing than fighting. They look nice, but when you get into a fight your dance kungfu isn’t going to help you not get your ass kicked." -Dan Guido
- 8. Windows Access Control *https://msdn.microsoft.com/en- us/library/windows/desktop/aa379557%28v=vs.85%29.aspx •Securable Objects •Files •Directories •Services •Registry Keys •Named Pipes
- 9. Windows Access Control *https://msdn.microsoft.com/en- us/library/windows/desktop/aa379563%28v=vs.85%29.aspx •Security Descriptor •Discretionary Access Control List (DACL) •Access Control Entries (ACE)
- 10. Windows Access Control *https://msdn.microsoft.com/en- us/library/windows/desktop/aa379563%28v=vs.85%29.aspx •Access Token •Container of user security info •SID, groups, privileges •Tied to process or thread
- 15. Mandatory Integrity Control *https://msdn.microsoft.com/en-us/library/bb625963.aspx •Security feature post-Vista •Assigns process Integrity Levels •Indicates “trustworthiness” of object
- 16. Windows Integrity Levels *Windows® Internals: Including Windows Server 2008 and Windows Vista, Fifth Edition
- 17. Windows Integrity Levels Low Medium High SYSTEM *https://msdn.microsoft.com/en-us/library/bb625963.aspx
- 18. Windows Integrity Levels *https://msdn.microsoft.com/en-us/library/bb625963.aspx Low Medium High SYSTEM UAC Just ask nicely…
- 19. The Setup… •Land on workstation as SKYNETLuigi via $method •Want to escalate privileges •Limited User -> Local Admin •Marketing isnt Admin… right?
- 20. Time to Level Up! •Admin somewhere else? •Creds in files •Exploit unpatched EoP bugs •Exploit insecure configs/apps •Weak Services DACLs •Weak File DACLs •AlwaysInstallEvelated •DLLs
- 21. Somewhere Else? •Luigi in “Domain Users” group •1 box “Domain Users” in “Administrators”
- 23. Somewhere Else?
- 24. Creds in Files •C:usersluigiDesktoppasswords.xls •C:>dir /b /s web.config •C:>dir /b /s unattend.xml •C:>dir /b /s sysprep.inf •C:>dir /b /s sysprep.xml •C:>dir /b /s *pass* •GPP •mushroomkindgomSYSVOL????
- 25. Windows EoP Buggzz •Enumerate missing patches •post/windows/gather/enum_patches •post/multi/recon/local_exploit_suggester •Pwn
- 27. Weak Service Permissions Accesschk.exe –qwcu “Authenticated Users” * Accesschk.exe –qwcu “Users” * Accesschk.exe –qwcu “Everyone” *
- 28. Weak Service Permissions •Can we edit the service config? •Can we edit the binary it points to?
- 30. Weak File Permissions •Look for writeable files •Autoruns? •Scheduled Tasks? Accesschk.exe –qwsu “Authenticated Users” c: Accesschk.exe –qwsu “Users” c: Accesschk.exe –qwsu “Everyone” c:
- 31. Weak File Permissions •Story time
- 32. Weak File Permissions •Story time •Main app binary writeable “users”
- 33. Weak File Permissions •Story time •Main app binary writeable “users” •Autorun on login
- 35. Weak File Permissions • “Nah bro, UAC”
- 36. Weak File Permissions • Admin logs in
- 37. Weak File Permissions • Admin logs in • Backdoored binary auto-executes
- 38. Weak File Permissions • Admin logs in • Backdoored binary auto-executes • Code execution at medium IL as admin (UAC)
- 39. Weak File Permissions •“One important thing to know is that UAC is not a security boundary.” *https://blogs.msdn.microsoft.com/e7/2009/02/05/upda te-on-uac/
- 40. AlwaysInstallElevated •Group policy setting that makes installing packages (.msi) convenient… •..Any .msi… •for everyone..
- 41. AlwaysInstallElevated reg query HKLMSOFTWAREPoliciesMicrosoft WindowsInstaller /v AlwaysInstallElevated reg query HKCUSOFTWAREPoliciesMicrosoft WindowsInstaller /v AlwaysInstallElevated
- 43. DLL Hijacking •Windows can dynamically load DLLs •If full path not used/missing, Windows executes DLL Search Order •Eg. •LoadLibrary(“ohnoes.dll”) vs •LoadLibrary(“c:program filesohnoes.dll”)
- 44. DLL Hijacking 1. The directory from which the application loaded. 2. The system directory. 3. The 16-bit system directory. 4. The Windows directory. 5. The current directory. 6. The directories listed in the PATH environment variable. *https://msdn.microsoft.com/en- us/library/windows/desktop/ms682586%28v=vs.85%29.aspx
- 45. DLL Hijacking 1. The directory from which the application loaded. 2. The system directory. 3. The 16-bit system directory. 4. The Windows directory. 5. The current directory. (Exploitable) 6. The directories listed in the PATH environment variable. (Exploitable) *https://msdn.microsoft.com/en- us/library/windows/desktop/ms682586%28v=vs.85%29.aspx
- 46. DLL Hijacking •Privileged app loads missing DLL + controllable search path element = pwned •Use Sysinternals Procmon •Include “.dll” •Include “NAME NOT FOUND” •Include folder in path
- 48. Conclusions •Know your network/apps •Don’t run as admin •UAC IS NOT A SECURITY BOUNDARY •Patch your shit •“Hack yourself first”
- 50. References/Resources https://www.insomniasec.com/downloads/publications/WindowsPrivEsc.ppt https://labs.mwrinfosecurity.com/system/assets/760/original/Windows_Service s_-_All_roads_lead_to_SYSTEM.pdf https://technet.microsoft.com/en-us/sysinternals/bb545027 http://www.greyhathacker.net/?p=738 Greyhat Hacking 4th edition Windows Internals 6th edition https://github.com/PowerShellEmpire/PowerTools/tree/master/PowerUp http://www.slideshare.net/mubix/windows-attacks-at-is-the-new-black- 26665607