In-Depth Understanding of Privilege Escalation Attacks

Privilege Escalation: What is it?

Privilege escalation takes place whenever a cyber-attacker deploys a bug, design flaw, or any form of a configuration error in an application or operating system for gaining elevated and direct access to the resources that are usually not available to a user. The attacker now uses the earned privileges for stealing confidential data and deploy malware with the intent of damaging the OS, server applications, and ultimately, the reputation of an organization. This type of attack on organizational data can be carried out even by an unsophisticated hacker for gaining the escalate privileges, the reason being most of the business organizations don’t use sufficient security measures and controls.

Types of Privilege Escalation

Following are the two types of privilege escalation attacks:

• Horizontal Privilege Escalation: In this form of attack, the hacker remains on the same user privilege level; however, they can access data and functionalities of other accounts that are not available with the existing account. Talking about web applications, an instance of horizontal privilege escalation could mean gaining access to other user’s profiles available digitally.
• Vertical Privilege Escalation: A vertical privilege escalation is considered to be dangerous than horizontal privilege escalation. Privilege escalation is often referred to as privilege elevation. In this form of attack, the attacker begins from a lower privilege account by obtaining the rights of a higher and powerful user, like a system administrator. Under this privilege escalation attack, the attacker can disrupt the systems and applications of others by getting away with login credentials and other vital data.

Working of Privilege Escalation

Attackers initiate this attack by exploiting this vulnerability inside a target system or an application, allowing them to override the limitations that a current user account has. They can even access the functionality along with data of other users. They might even obtain privileges of a system admin or any other powerful user in the business organization.

Common Privilege Escalation Methods

It is clear that in a privilege escalation attack, the attacker aims to gain access to higher-level privileges and enter the critical IT systems without getting caught.

Attackers deploy several techniques for achieving privilege escalation. Some of the commonly used methods include the following:

Access Token Manipulation

In this type of privilege escalation method, it exploits the method similar to Windows for managing the Admin privileges. In standard practice, Windows uses access tokens for determining the owners of all processes that are running. Under this method, the primary intent of the hacker is to trick the system and make it ‘believe’ that the processes that are currently running are owned by someone else and these users are different from the ones who started it. Whenever this happens, the process also takes over the security context that is linked with the new token.

Mitigating The Threat

The access tokens are the inevitable components of a security system present in Windows and these can’t be ignored at any time. Although, the attacker might already be having access to an administrator-level for leveraging this technique. Thus, the companies must define the access rights in sync with the least-privilege principle and ensure that these access rights are being regularly monitored. Companies must also keep a strong watch on the privilege accounts for responding to suspicious activities that might be performed on such accounts.

Bypassing the User Account Control

Windows is well-known for having a well-defined structured mechanism that can control the privileges of all users present in the network. The User Account Control (UAC) is a feature that bridges the gap between ordinary users and users having admin-level privileges. With UAC in place, it restricts the application software to the permissions of a standard user until the admin enhances the privileges. With this method, applications selected by the admin-level user will have privileges, thereby, preventing the malware from compromising the OS.

This technique has certain shortcomings, as well. In case the UAC protection levels of a system are defined to the highest level. Some Windows programs can elevate the privileges or even execute the Component Objects Model (COM) objects without intimidating the user.

Mitigating The Threat

The businesses must check their IT environment for all common UAC bypass weaknesses regularly to make sure that they are aware of the current risks to the systems and address the issues. Additionally, businesses can review their accounts regarding which of them are in local admin groups in systems and eliminate regular users from such groups.

Using Valid Accounts

Cybercriminals can use any of the credential access techniques like- credential dumping or any other for obtaining the user’s account credentials. As the attackers gain access to an organization’s IT network, they utilize the compromised and weak credentials for bypassing access controls deployed on various systems. Cybercriminals might even win illegal access to the remotely located systems and services through means of a VPN, remote desktop accesses. The biggest concern in this privilege escalation technique is the overlapping of credentials and permissions in the networks since the attackers can swiftly switch accounts to get to a higher access level.

Mitigating The Threat

One of the simplest ways to mitigate this threat is to change the passwords of admin accounts regularly. Besides changing passwords frequently, businesses must also implement robust password policies, so that there are unique and complex passwords on all systems. The companies must also keep a vigilant watch on the user behavior and have information about the permission level of every user in the system for quick detection of activities of an attacker.

Why is Preventing Privilege Escalation Important?

Privilege escalation might not be the end goal of an attacker. It is often seen as the cover for a more specific cyberattack that allows other cyber-attackers to deploy a malicious payload and alter the security settings of the targeted systems. Privilege escalation attacks represent a major online vulnerability that includes a malicious attacker to gain illegal access to a privileged user account and get away with crucial confidential and sensitive information.

How to Protect Systems?

Attackers can deploy various techniques to achieve their target systems. To accomplish the basic agenda of any privilege escalation, they need to have access to a lower privileged user account for gaining access. Thus, the regular user accounts serve as the first line of defense. One should take adequate yet simple following steps to assure robust access controls-

Enforcing Strong Password Policies

Enforcing strong password policies is one of the simplest methods to ensure the security of user accounts. Passwords for every statement in the system needs to be strong enough for enhanced security, without causing any difficulty to the users. The strong passwords can be difficult for a cyber-attacker to guess, thereby reducing the chances of penetration in the system.

Creating Specialized Groups Having Least Privileges & File Access

Companies must use the rule of having the least set of permissions that are required to overcome risks related to any compromised user account. This rule can be deployed for both- the normal users as well as the higher-level admin users. By offering too many privileges to the admin-level accounts can provide the attackers a single window for accessing the system/network.

Business applications also serve as the most accessible entry point for any privilege escalation attacks. Thus, businesses need to secure these as well and here are the following some conventional methods for securing business applications-

Using a Vulnerability Scanning Tool

The businesses must use a vulnerability scanning tool that can check their systems and web applications against all the possible threats and vulnerabilities. Most of the scanning tools available today are developed to match-up with the changing dynamics of the security domain. All these proactively determine any such vulnerabilities and inform the users so that they can take the due course of action.

Avoiding Common Program Errors in Applications

Businesses must follow the best development methods for avoiding any common programming flaws that are usually targeted by attackers. Some common programming errors include- buffer overflows, code injections and any invalidated user input.

Securing Databases

The database systems also serve as soft targets for attackers where the modern web applications and frameworks store their crucial data in these databases. When an attack can take place through an SQL Injection, the attackers gain access to the database data by altering the database structure with malicious SQL commands. Through SQL Injection attacks, the attackers use the stored database information for any further attacks.

Concluding Remarks

There are no full-proof methods that can secure a business secure against emerging cybersecurity vulnerabilities and threats. However, companies must deploy some of the basic yet effective techniques to minimize the threat exposure and determine such risks at a budding stage. To combat privilege escalation attacks, businesses must identify the weak entry spots in their IT system and follow the practice of assigning the least privileges and be aware of all changes taking place on the networks and system accounts.