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Authentication and Access Attacks

Authentication and access attacks cover the techniques adversaries use to break into systems, escalate privileges, and move laterally across a network. Methods range from credential theft and brute-force guessing to replay attacks, trust exploitation, and authentication bypass.

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About this video

Authentication and access attacks encompass the range of techniques an adversary uses to break past the security controls that protect systems, networks, and the resources connected to them. Credentials represent the most direct path in, functioning like a key to a front door. Attackers either obtain those credentials through theft or purchase on criminal marketplaces, or they attempt to determine them through guessing and brute-force methods. Not every attack, however, requires knowing a valid username and password combination. Several techniques exist for gaining access without direct credential knowledge. A replay attack captures authentication data in transit and resubmits it to impersonate a legitimate user. Trust exploitation takes a different approach, using a system or account the target network already trusts as a pivot point to reach otherwise inaccessible resources. Authentication bypass methods, such as SQL injection against a vulnerable web application, can grant access to data and functionality without any valid credentials at all. Even after initial access is achieved, the level of permission granted may be insufficient to carry out the intended attack. Privilege escalation addresses this gap by exploiting weaknesses in the operating system or application layer to elevate a standard user account to administrative or root-level access. Understanding the full spectrum of these techniques, from initial entry to privilege escalation, is essential for both offensive security practitioners and defenders working to identify and close the vulnerabilities that make these attacks possible.

What you'll learn

Identify common authentication and access attack techniques, including credential theft, replay attacks, trust exploitation, authentication bypass, and privilege escalation
Distinguish between attacks that require valid credentials and those that circumvent authentication altogether

What's covered

Authentication & Access Attacks

Credential Access
- Know or Steal Credentials
  - Username & Password
- Guess Credentials
- Replay Attack
  - Replay Captured Credentials
Trust Exploitation
- Leverage Trusted Device
- Pivot to Other Resources
Bypass Authentication
- SQL Injection
- Exploit Web App Weaknesses
Privilege Escalation
- Regular User to Super User
- Escalation Tools

Key terms

Authentication: The process of verifying the identity of a user, device, or system.
Privilege Escalation: An attack that exploits vulnerabilities to gain higher-level access than originally authorized.
SQL Injection: An attack that inserts malicious SQL code into a query to manipulate a database.
Spoofing: An attack where an adversary impersonates a trusted entity by falsifying data such as an IP address or email address.
Replay Attack: An attack in which a threat actor captures valid network data — such as an authentication token or session credential — and retransmits it later to impersonate the original user or device without needing to know the underlying password.
Trust Exploitation: An attack technique that leverages the trusted relationship between systems or users to gain unauthorized access to resources that would otherwise be inaccessible.
Authentication Bypass: A technique that circumvents authentication mechanisms entirely, allowing an attacker to gain access without supplying valid credentials.
Credential Theft: The act of stealing usernames, passwords, or other authentication data to gain unauthorized access to systems or accounts.

Topics

Authentication Credential Theft Privilege Escalation Replay Attacks Authentication Bypass Lateral Movement Cybersecurity

Transcript

Somehow we're going to need to gain access into the systems that we're trying to attack, either through some sort of authentication or another method. Not all attacks need to gain some sort of authentication or access into a system, but many do.

An adversary is going to try to hack into a system and leverage it to gain access to other systems. There's a lot of access here: a lot of access to the original system, to the network, and to resources on the network. The thing is that there are a lot of guards in place to protect systems, so that we can't gain access to those systems. But there are still ways and mechanisms for us to be able to get access.

One of them is to figure out what some sort of known credentials are — what is a way that we can get into it by a username and password. Sometimes we don't necessarily need to know a username and password to gain access into the system, and that's where something like a replay attack comes into place. Or we could do a trust exploit, by gaining access through something else. Or we could bypass authentication altogether. There are ways to do that as well.

Credential Access: The Front Door

I like to think of credential access as being the front door. When you walk up to a house, what we have is the front door, which is where you usually enter in. But there's a key to that front door, and we need to unlock that door. So what is the key? We either know what that key is, we have it, or we have to guess at what that key is. So there are pretty much two categories of this: we either know it or guess it. There are certain ways that we can steal it or purchase it, and there are certain ways that we can guess at it.

Replay

To get into a house, we wouldn't necessarily need a key. That is, we could do something like a piggyback attack, where when the door is open we can follow somebody into that house. So this is kind of like a replay credential, where if we see the credentials that are being sent, we could just replay those to get into that system. This is why we have replay: we could just replay those credentials.

Trust Exploitation

Let's say we're wanting to gain access to this system right here, but the problem is that this system doesn't trust us. We're not going to be able to access that system directly. However, there is another system on here that is a web server, a web server which we can reach, and we happen to know that there's some sort of exploit that we can leverage to get onto this system. Since everything within this organization is trusted, we now have access to other systems on this network.

So trust exploitation is leveraging the trust of one device, or one person, on the network in order to be able to access some other resource on that network.

Bypassing Credentials

We don't necessarily always need credentials. There are times when we can bypass credentials. Maybe somebody's created a web app on some sort of server and it has some weaknesses. Maybe one of its weaknesses is a SQL injection. We could do a SQL injection attack on this server right here, and then be able to gain information and carry out what we want to do without ever knowing the actual credentials for the system. So we don't always need to know what the credentials are.

Privilege Escalation

Even when we do have access into a system, many times it's not the proper access that we need to carry out the attack. This is where privilege escalation comes in: perhaps we're just a regular user on the server, and then need to escalate it to be a super user in order to be able to leverage that and carry out our attack. So there are ways that we can do privilege escalation on these devices.

There are a lot of tools that can help us out with this, and there are many more out there.

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