Privilege escalation is one of the most exploited stages in the cyberattack lifecycle. It refers to the act of gaining higher-level permissions or access rights within a system, often beyond what is legitimately authorized for a user or process. Whether conducted by external threat actors or malicious insiders, privilege escalation can serve as a gateway to full system compromise, data breaches, and persistent control over IT environments. For cybersecurity professionals, understanding privilege escalation is critical to stopping attackers in their tracks.
This guide dives deep into privilege escalation, covering its types, techniques, common attack methods, real-world techniques, and best practices to protect your systems.
Vertical Privilege Escalation
Horizontal Privilege Escalation
Credential Exploitation
Exploiting Vulnerabilities
Misconfigurations
Malware Deployment
Social Engineering
Windows Techniques
Linux Techniques
Frequently Asked Questions (FAQs)
At its core, privilege escalation is about gaining higher or unauthorized access levels within a system. Attackers use this to bypass restrictions, modify system settings, access sensitive data, or plant backdoors.
Key Breakdown:
Vertical Privilege Escalation involves moving from a lower privilege level (e.g., a standard user) to a higher one (e.g., admin).
Horizontal Privilege Escalation happens when attackers access the privileges of another user with the same privilege level.
For instance, an attacker may start as a standard user with minimal permissions but later gain administrative access by exploiting system vulnerabilities, stolen credentials, or weak configurations.
Think of this as a user gaining unauthorized superpowers. Hackers often aim for “vertical” escalation to gain root, administrator, or system-level access.
How it works:
Exploiting bugs in operating systems to elevate process privileges.
Bypassing User Account Control (UAC) in Windows systems.
While not aiming for higher permissions, this tactic involves accessing another account at the same level, often to steal data or mislead investigations.
Example:
A user account accessing another user's files without elevated permissions, using stolen cookies or by session hijacking.
Both horizontal and vertical attacks are highly damaging. The former can erode trust, while the latter opens up unrestricted access to crown-jewel systems.
Privilege escalation isn’t just a minor annoyance; it’s the backbone of many devastating attacks. Once elevated access is achieved, attackers can cause irreversible damage.
Top Risks Include:
Data Breaches: Exposure of sensitive customer or organizational information.
Persistence: Attackers create hidden backdoors or rogue accounts for future system access.
Evasion: Security tools may be corrupted or disabled.
Complete Network Takeovers: Elevated privileges often allow attackers free rein across the environment.
Privilege escalation was used by threat actors in several famous attacks including NotPetya, the SolarWinds attack, and ZeroLogon attacks, all of which caused billions in damages.
Attackers employ a mix of creativity and exploitation here. Here’s a breakdown of the most common routes used to escalate privileges:
Passwords (and their improper handling) are a hacker’s favorite target. Techniques include:
Password Reuse and Stuffing
Pass-the-Hash (PtH) attacks to use password hashes.
Pro Tip: Always enforce multi-factor authentication (MFA). A second layer of defense makes stolen passwords far less effective.
Attackers target flaws in systems, like unpatched code or application mismanagement, to bypass privilege checks. Frequent culprits include privilege escalation bugs in Windows and Linux kernels.
Regular patching? Not negotiable.
Misconfigured systems are a goldmine for attackers. Common slip-ups include:
Overly permissive SUDO configurations in Linux.
Default credentials remaining unchanged.
Rootkits and spyware are notorious for executing privilege escalation in stealth mode to avoid detection.
Phishing is still wildly effective. A simple link can give attackers the keys to your kingdom.
Best defenses? A knowledgeable workforce trained in spotting phishing attempts and a Zero Trust framework in place.
Access Token Manipulation: Hijack tokens to convince the system to assign admin privileges.
DLL Search Order Hijacking: Replace valid DLL files with malicious ones and hijack processes.
Exploiting UAC Bypasses: Reduce the effectiveness of user prompts to gain admin access undetected.
Linux attackers often exploit kernel bugs or abuse SUDO permissions.
Kernel Exploits: Gaining root access by finding unpatched vulnerabilities in Linux.
SUDO Misuse: Poorly configured SUDO can allow hackers to run commands as root.
How Professionals Stay Ahead:
Audit Logs for unusual login attempts or unexpected command executions.
Endpoint Detection and Response (EDR) programs for real-time monitoring.
Identity Threat Detection and Response (ITDR) to detect abnormal behavior like privilege escalation attempts.
Stay proactive. The earlier you can detect privilege escalation, the less harm is done.
Must-Implement Defenses:
Enforce Least Privilege Access (LPA): Only give users the access they need. No more, no less.
Deploy MFA: Harder for hackers to go higher when MFA is enforced.
Patch, patch, patch!: Eliminate known vectors by patching bugs promptly.
SUDO Controls for Linux: Limit admin command access and audit SUDO files frequently.
Security Awareness Training: Teach teams to spot phishing, unusual behavior, and weaknesses.
Credential Hygiene: Use strong, unique passwords and rotate them strategically.
Failing to address privilege escalation can lead to:
Ransomware Propagation
Regulatory Fines from non-compliance.
For instance, the Polkit vulnerability allowed attackers root-level access for months before patches went out, showcasing the devastation possible through ignored escalation concerns.
Remember, protecting against privilege escalation requires a combination of strategies, proactive defenses, and continuous monitoring. Don’t leave access doors wide open. Book a demo to learn how the Huntress Managed Security Platform can help you today.
See how the global Huntress SOC can augment your team with 24/7 coverage and unmatched human expertise.
