What Is a Watering Hole Attack? Detection and Prevention

We already know that cybercriminals exploit the weakest link in your IT networks. The best defense against these exploits comes down to safeguarding the most vulnerable entry points.

But what if the weakest link in your cybersecurity defense lies beyond your IT network itself? You can set up impenetrable defense systems for your enterprise IT network, but that doesn’t stop cybercriminals from compromising a secondary target...that just so happens to be a frequently used gateway entry point to your network.

This is precisely what a watering hole attack does. Let’s take a look!

What is a watering hole attack?

One type of cyberattack, in a watering hole attack, hackers target online platforms or websites that are frequently browsed by their target victims.

On these websites/platforms, the hacker doesn't directly attack the victim. Instead, they compromise the victim's trusted website by injecting malware or malicious code.

As soon as an unsuspected user browses the infected site, a malware or similar kind of malicious payload is delivered to their device. Consequently, the hacker gets unauthorized access or monitoring capability over the victim's personal device.

But that's only the beginning of the damage done: A website may remain infected for weeks or months before the cybersecurity team detects the watering hole attack. Detecting becomes quite challenging because of the stealthy nature, as attackers often exploit trusted websites with very small noticeable changes. (Hence the rise in terms like detection engineering and TDIR: threat detection, investigation, and response.)

But why is this cyberattack named "watering hole" attack?

Origin of the term

The term basically originates from the kingdom Animalia. In wildlife, predators are often observed waiting near watering holes, targeting animals who gather to drink.

Similarly, in the context of cybersecurity, attackers "wait" for their targets who are likely to gather at certain websites. The opportunistic and stealthy nature of the hackers and the way they rely on the behavior of a victim are highlighted in the analogy.

Other terms for watering hole attack

There are some other terms of watering hole attacks:

• Supply chain web attacks: This occurs when a third-party website that is part of a supply chain is compromised.
• Strategic web compromises: This reflects the targeted nature of watering hole attacks.
• Web watering hole attacks: Highlights the usage of websites as the medium of attack.

All of these terms highlight the indirect and strategic nature of a watering hole attack, focusing on how intermediaries (websites, other platforms) are used to attack the target.

The watering hole attack is highly effective because it takes advantage of the trust a user has over a frequently visited legitimate site. Thus, making the attack quite difficult to detect. Watering holes are often used for:

• Data theft
• Espionage 
• To set up base in a network for more widespread operations, often via lateral movement

In the cybersecurity domain, it remains a significant threat, requiring organizations to secure and regularly assess the platforms and websites they rely on.

How do watering hole attacks work?

Watering hole attacks are any attacks that identify an external, trusted but vulnerable service frequently accessed by users of a given organization. Bad actors exploit these vulnerabilities to deliver a malicious payload to the organization’s network. This technique can look just like a zero-day attack, exploiting an unknown or unpublicized vulnerability.

Let’s illustrate. This is what a watering hole looks like: you have your own IT network that you can fully control and protect against network intrusions and exploits.

Next, there’s an IT service, an app, a tool, a website or technology that is frequently used by your employees. Let's use the example of Slack, which many organizations rely on for both colleague communication and integration with common work apps. These services, Slack and others, may be integrated with your network or interact directly with your employees, accessing data and communicating a variety of legitimate traffic requests.

These services are controlled by a third party, which of course are vulnerable to cyberattacks. By exploiting the vulnerabilities, these third-party services can act as a “watering hole” to deliver a malicious payload to your organization.

(Related reading: third-party risk management.)

Role of emails in watering hole attacks

To understand the mechanism of watering hole attacks, you should explore the various techniques which hackers use. This includes emails, which play an important role in initiating an attack.

Emails can act as an initial delivery mechanism. An attacker may send a phishing email that contains a normal-seeming, suspicious link. Clicking the link may redirect the unsuspecting user to visit a compromised website, leading to a watering hole attack. Once the user accesses the infected website, a malicious payload attacks their system.

The attack is one thing, but this email can also help the attackers gather more information about you: insights on a user's preference, behaviors, or the services they frequently access. This further helps attackers to identify potential targets for watering hole attacks.

Because of this, as a broader defense strategy, you should monitor email communications and train your employees to recognize phishing attempts.

(Related reading: website monitoring and security monitoring.)

Stages in watering hole attacks

The watering hole attack includes the following stages:

1. Gathering intelligence
2. Analyzing the intel
3. Preparing the attack
4. Executing the attack

Phase 1: Intelligence gathering

The attack targets users from a specific organization or industry vertical because these users, this specific audience, are likely to visit a particular service frequently.

The idea behind choosing a frequently visited site as a target is to launch an advanced persistent threat (APT) that would eventually help the adversaries bypass your network security systems.

Phase 2: Analysis

Once the target service is identified and compromised, the attackers obtain intelligence into:

• User behavior
• The network response to traffic requests

Multiple tools and techniques may be used to identify and exploit vulnerabilities in the target service.

Phase 3: Attack preparation

At this stage, the chosen attack is launched on the target service. Common attacks here include SQL injections, cross-site scripting (XSS), and zero-day exploitation.

Phase 4: Attack execution

When the watering hole is ready to launch the attack on the target network of the organization, the malware payload is delivered first from the compromised service to the user and then to the IT network of the organization.

At this stage, the malware may propagate and gain more intel into network behavior as any APT attack.

Watering holes use open windows instead of doors

Many organizations build multiple layers of security around their IT networks. The deceptive nature of watering hole attacks, however, make clever use of recent trends in the enterprise IT landscape — like bring your own device (BYOD) and remote working models.

During the analysis phase of the attack, adversaries gain information into repetitive user behavior. They exploit the predictability and behavioral patterns of the victims. They combine this with vulnerabilities in the watering hole service. This allows them to deliver the malware payload. The payload is then spread across secure enterprise IT networks.

Reasons & motive behind watering hole attacks

The motivation behind a strategically planned cyberattack like a watering hole attack varies widely depending on what the attacker wants. Although financial gain is the most common reason, it is not the only reason for which these attacks occur:

Political or religious motivation

State sponsored hacktivist group can use watering hole attacks to target government entities or individuals to disrupt their operations, spread propaganda, or gather intelligence. These attacks are also used to sabotage critical infrastructure or spy on opposition.

Likewise, certain extremist groups can target organizations or individuals of opposing religious affiliations to deface their websites, spread malware, or promote their ideology.

Financial motivation

This includes stealing information like credit card details, customer data, or other confidential or intellectual property (IP). Attacks can also aim to install ransomware for money extortion from a victim.

Examples of watering hole attacks

Let's discuss a few notable examples of watering hole attacks.

• In 2013, attackers targeted the U.S. Department of Labor website to gather intelligence on users accessing nuclear-related content.
• In 2016, Polish banks discovered malware that originated from the Financial Supervision Authority servers.
• In 2017, the popular NotPetya ransomware attack that wiped data from major public institutions, energy companies and banks used the watering hole attack through a Ukrainian accounting software website, MeDoc.
• EvilBamboo, a threat actor targeted Tibetan, Taiwanese and Uyghur organizations and individuals by creating fake social media profiles and websites in September 2023. The attackers used the platforms to distribute spyware and deploy browser based exploits, compromising the visitor's devices.
• From November 2023 to July 2024, APT29 (an advanced threat group) compromised the websites of Mongolian governments for conducting watering hole attacks. They targeted the site audiences with vulnerable devices with spywares, leading to data breaches and unwanted access.
• In December 2024, multiple watering hole attacks were reported by JPCERT/CC (Japan Computer Emergency Response Team Coordination Center), where the attackers compromised legitimate sites for malware distribution. Instead of exploiting software vulnerabilities, the attackers relied on social engineering techniques. As a result, they successfully tricked users into executing malicious files.

These are all high-profile attacks. They were executed by compromising different websites or services, not the target networks directly. This threat vector highlights a pressing reality. Security teams are responsible for securing their own IT networks.

However, a secondary target can act as a hidden gateway. Such gateways can allow attackers to infiltrate otherwise secure networks.

Protecting against third-party risk

To defend against this threat, business organizations must reevaluate their support for third-party services and network access mechanisms facing risks of watering hole attacks.

Since remote working models and BYOD are here to stay, organizations can establish policies to better control and govern remote access to their own data and services. An important strategy in this regard, is to rely on advanced Identity and Access Management (IAM) models that provide granular access controls over all data and resources shared to remote devices.

For instance, the Attribute Based Access Control (ABAC) can be designed to evaluate every request based on dynamic environment parameters and attributes. Instead of using fixed predefined rules, the ABAC model learns to identify patterns of anomalous behavior. This allows it to detect deviations from predictable user behavior and traffic requests, identifying them as potential network intrusions.

Since watering hole attacks rely on repetitive user behavior to deliver ATP and malware payloads to your network, the ABAC model effectively prevents such attacks.