Despite being something old, from the 1990s, few people know how pass-the-hash attacks work.

Keep reading the article to find out!

Where Did the Name “Pass-the-hash” Come From?

Pass-the-hash attacks occur when an attacker steals a user’s credential with a hash function.

Without “breaking” this function, the attacker reuses it to trick an authentication system into creating a new authenticated session on the same network.

For those who are not aware of it, a hash function is any algorithm that maps large, variable-sized data to small, fixed-sized data.

Hash functions are widely used in order to verify the integrity of downloads, search for elements in databases, or transmit and store passwords.

Hence the “pass-the-hash” name, which literally means this—exactly what attackers do through this attack.

How Are Pass-the-hash Attacks in Information Technology Classified?

Pass-the-hash attacks are primarily a lateral movement technique.

This means hackers are using the hash to extract additional information and credentials after they have already compromised a device.

By moving “sideways” between devices and accounts, attackers can “pass the hash” to get all the correct credentials from someone else.

With this, they can eventually “scale up” their domain privileges and access more influential systems, like an administrator account on their personal computer, without even needing their password.

Another interesting fact is that most of the movement performed during a pass-the-hash attack uses a remote software program, such as malware.

What Operating Systems Do Pass-the-hash Attacks Work On?

Typically, pass-the-hash attacks target Windows systems.

However, they can also work against other operating systems, in some cases on any authentication protocol such as Kerberos.

Windows is especially vulnerable to these attacks because of its single sign-on function.

This function allows users who, by entering the password only once, can access all the features they want.

The single sign-on function also requires users’ credentials to be cached on the system, making it easier for attackers to access.

That is one of the reasons why it is so important to know the 7 Tips to Prevent Cyberattacks While Remote Working.

How Do Pass-the-hash Attacks Work?

To perform a pass-the-hash attack, the attacker first obtains the hashes of the targeted system using any number of hash dump tools, such as fgdump and pwdump7.

The attacker then uses these tools to place the obtained hashes into a Local Security Authority Subsystem Service (LSASS).

Pass-the-hash attacks are often targeted at Windows machines due to the security vulnerability of NTLM (New Technology Local Area Network Manager) hashes once administrator privileges have been obtained.

These attacks often trick a Windows-based authentication system into “believing” that the attacker’s endpoint is the legitimate user’s endpoint.

Thus, the system automatically supplies the necessary credentials when the attacker tries to access the targeted system.

And all this can be done, as already said, without the need for the original password.

The key used by attackers to perform these types of attacks is the NTLM hash, which is nothing more than fixed-length mathematical codes derived from passwords.

NTLM hashes allow the attacker to use compromised domain accounts without extracting the password in plain text.

This is because computer operating systems such as Windows never actually send or save user passwords on their network.

Instead, these systems store passwords as encrypted NTLM hashes, which represent the password, but cannot be reverse-engineered.

NTLM hashes can still be used in place of a password to access various accounts and resources on the network.

For an attacker to be able to access LSASS, they must successfully compromise a computer to the point where the malware can run with local administrator rights.

Therefore, this is one of the biggest obstacles to pass-the-hash attacks. And knowing how to securely control your privileged accounts with PEDM is another big obstacle, too.

Once a Windows-based machine is compromised and the deployed malware is given access to local usernames and NTLM hashes, do you know what happens?

The attacker can even choose whether to get more credentials or try to access network resources using privileged user credentials.

By gathering more user credentials, an attacker can retrieve the credentials of users who have separate accounts on the Windows machine, such as a service account, or who still have remote access to the computer with an administrator login, for example.

Remote information technology (IT) administrators connecting to the compromised Windows machine will expose their NTLM username and hash to the now-integrated malware.

An attacker with IT administrator credentials can then move “sideways” across networked devices.

The “lateral movement” is an effective way to search for users with elevated privileges, such as administrative rights to protected resources.

Privilege escalation can be achieved by locating the credentials of an administrator with greater administrative access.

These elevated features can also include access to customer databases and email servers.

What Can Pass-the-hash Attacks Do to My Computer?

Because this type of attack exploits the features and capabilities of the NTLM protocol, the threat can never be completely eliminated.

Once an attacker compromises a computer, pass-the-hash becomes just one of the malicious activities that can be performed.

A 2019 study found that 95% of its 1,000 respondents experienced a direct business effect from pass-the-hash in their organizations.

About 40% of these attacks resulted in lost revenue and 70% incurred increased operational costs.

No wonder that many IT experts consider pass-the-hash attacks to be among the top cybersecurity vulnerabilities in Industry 4.0.

When it involves ransomware protection, it is better to be safer than sorry, isn’t it? To achieve this goal, a vigilant outlook and the right security software are essential, since a moment of carelessness is enough to fall victim to a cyberattack.

You probably know what ransomware is, but it is worth remembering: it is a type of extortion malware that can lock down your computer and then demand a ransom to return the operating systems. In May 2017, for example, the WannaCry variant spread around the world and reached more than 100 million users, claiming some major victims, such as the UK’s National Health Service (NHS). It infected more than 230,000 computers in 150 countries in just one day.

Since then, ransomware has spread around the world, with new types and new hits, and with that, cybersecurity solution makers have increasingly focused their actions on preventing attacks by this “pirate” of nowadays. And to support the fight against this increasingly frequent cybercrime, we launched the #stopransomwareattacks campaign on our social networks, with the aim of raising awareness among IT professionals and society about the variety of ways this malware appears on operating systems and the risks caused by a simple click.

What are the kinds of attacks?

The forms of attacks are diverse: ranging from messages about unlicensed applications to false claims about inappropriate content, in some cases resulting in the payment of fines or the need to restore devices to factory settings.

From the most aggressive to the most imperceptible forms, some of the main ransomware variants are:

Petya: It goes beyond hacking into files and can bring the entire system to a halt, causing devastating results.

zCrypt: It does not attack files directly; it acts like a classic virus, acting on recently handled files to boost the impact.

Jigsaw: This attack begins with a simple greeting message, followed by a ransom demand, threatening the victim with the removal of all their data within 72 hours.

Wannacry: The infection by this ransomware was indeed a global epidemic, scaring everyone and causing companies and government agencies to rush to seek protection solutions. The losses caused by this malicious software are estimated to have totaled $4 billion worldwide.

Ransomware, in all its forms and variants, represents a significant threat to both independent users and enterprises. That’s why it’s even more important to be aware of the threats it portrays and be extra careful in eventualities. 

Join the #stopransomwareattacks campaign! Post pictures on your social media networks with signs written with the hashtag, tag senhasegura’s profile and share with friends… Let’s stop the dynamics of malicious activity!

If you want to know more about how ransomware acts on a system, senhasegura will promote the webinar “Dissecting Ransomware Attack – Protecting your Company Accesses” on the October 26th at 3pm (CET), with a live demonstration by Cybersecurity Researcher, Filipi Pires, and by senhasegura’s System Analyst, Gabriel Oba, who will clarify all doubts with a highly conscious approach to the use of devices and what is the adequate product to mitigate the risks of this type of malicious attack.