Watering Hole Attacks: Exploiting Trusted Websites for Cyber Intrusion

A watering hole attack is a cunning type of cyber intrusion that involves compromising trusted websites to deliver malicious payloads to its visitors. This attack draws inspiration from watering holes in the natural world, where predators patiently await their prey at shared water sources. 

Once a threat actor compromises a trusted website, the compromised site serves as a launchpad to deliver malicious payloads to unsuspecting visitors. The concept of a watering hole attack underscores a chilling reality about today’s digital landscape—even familiar territories harbor hidden threats. 

This article takes a deep dive into watering hole attacks by examining how they work, highlighting some pertinent real-world examples, and pointing out some actionable strategies to mitigate and prevent them from affecting your business or employees. 

What is a Watering Hole Attack?

A watering hole attack is a targeted cyber attack in which the attacker figures out which websites an organization or a specific group of people frequently visit, and then attempts to compromise one or more of these sites to exploit those visitors/users. The aim is to deliver malware to people using the compromised site rather than directly trying to deliver malware via email attachments or other methods. These attacks are often effective because they get around the security defenses of targets by hitting victims external to the ultimate target. 

How Watering Hole Attacks Work

The previous description of watering hole attacks only scratched the surface of what happens in these incidents. Here’s a more granular breakdown of the watering hole attack process:

1. Reconnaissance

First, the threat actor (or actors)  decides on a specific organization or group of individuals they want to target. The instigator then investigates which websites the target person or group frequently visits. Web traffic analytics or even infiltrating the organization to determine which internal or external resources employees commonly access are both useful strategies here. 

2. Compromise the Website

Once the attacker has identified the website(s) visited by a set of targets, the next step is to compromise one or more of these sites. The most common method is to find and exploit vulnerabilities in the website’s code, server, or other infrastructure components.  Another possible route is where the attacker obtains login details for the website (e.g. by phishing or keylogging). 

3. Introduction of Malicious Code

After compromising a chosen website, the attacker typically injects malicious code into its content. This step sets a trap for the unsuspecting visitors who think they are interacting with the website as normal. 

Often, hackers embed exploit kits in web pages to exploit vulnerabilities in visiting users’ systems. When a user visits the compromised site, the exploit kit runs a series of tests to determine which vulnerabilities exist on the user’s machine and then delivers a payload tailored to exploit these vulnerabilities. Malicious scripts and iframes can run automatically each time a visitor loads a specific page on the site. 

4. Drive-by Downloads

Drive-by downloads are a popular technique used in watering hole attacks. The technique involves automatic downloading of malicious software to a user’s system when visiting a particular web page. 

These drive-by-downloads downloads occur without the user’s consent, and often without their knowledge. Aside from so-called silent infections, malicious code may trigger pop-ups or fake alerts prompting users to download software updates or other seemingly legitimate tools. However, when the user agrees, they inadvertently download and install malware.

5. Exploitation

After infecting a user or group of user systems with malware, the real exploitation occurs. The malware communicates back to the attacker’s server and allows them to control or spy on the infected machine remotely. The attacker can steal sensitive data, like login credentials, financial details, or proprietary information. If the infected machine is part of a larger network (like a company’s internal network), the attacker can attempt to move laterally, exploit other systems, and gain additional footholds. These attacks also enable hackers to establish networks of zombie computers that they control remotely as part of a botnet; these networks are often used to inundate sites or apps with large volumes of traffic in a distributed denial of service attack.. 

Watering hole attacks might end at the exploitation phase, or there might be further attempts to maintain access to the compromised system for future activities. Installing special malware known as backdoors enables the threat actor to regain access even if the endpoint security tools detect and remove the initial malware. 

Recent Examples of Watering Hole Attacks

To add context to the threat of watering hole attacks, here are some real-world recent examples and their consequences. 

• An advanced watering hole attack from 2021 targeted visitors to various Hong Kong websites and exploited zero-day flaws in machines running macOS. 
• Advanced persistent threat actor Earth Kitsune compromised a North Korean website in 2023 and used that site to distribute malware to each visitor trying to watch a video on the compromised site.  
• In 2022, Iranian hackers targeted shipping, logistics, and financial services companies in Israel by compromising a legitimate Israeli shipping company’s website and serving malicious JavaScript to visitors. 

Watering Hole Attack Use Cases

If the real-world watering hole attack examples didn’t fully crystallize the realm of possibilities, here are three use cases that exemplify more ways hackers might use this cyber threat. 

1. Exploiting websites frequented by government employees to gain access

A nation-state actor seeks to gather intelligence from a rival country’s government agencies. After conducting preliminary research, the threat actor identifies a popular internal portal that government employees often use to download official forms and access internal news. This portal becomes the attacker’s main target. the portal and embeds malicious code. When employees of the government agency visit the portal, their computers become infected, which enables the attacker to gather credentials, access classified documents, and gain a deeper foothold in the agency’s network.

2. Targeting websites visited by professionals for industry-specific information

Professionals in the oil and gas industry frequently visit a particular association’s website to get updates on regulations, industry research, and best practices. An attacker with interest in this sector aims to manipulate market prices or acquire proprietary drilling techniques. 

he threat actor targets this association’s website, compromises it via social engineering techniques, and embeds an exploit kit. When industry professionals visit the site, they unknowingly download malware tailored to seek out and transmit proprietary data back to the attacker. This can lead to massive industry disruptions or unfair competitive advantages.

3. Gaining access to competitor or partner websites to gather intelligence

Company A and Company B are top competitors in a hypercompetitive market. Company A aims to get a leg up and decides to engage in corporate espionage. They learn that Company B’s R&D team frequently collaborates using a specialized software platform accessible through a web portal. 

A black hat hacker hired by Company A from a dark web marketplace compromises this portal and inserts a malicious script. As members of Company B’s R&D team access the portal, their systems get infected, and key project data, designs, and internal communications are funneled back to Company A to give them a strategic advantage in the market.

Mitigation Strategies Against Watering Hole Attacks

There’s no getting around the fact that watering hole attacks are hard to counter. Since they target an intermediate rather than a company directly, specific security defenses are tricky to implement. 

However, there are some available measures to help thwart these attacks. The best defense requires monitoring network traffic to trusted external sites and partners. It’s also helpful to have well defined zones within your network infrastructure to make lateral movement more difficult and restrict the systems that have Internet access. 

Here are three of the high-level mitigation strategies you should definitely consider:

1. Regular Security Audits

Whether it’s penetration testing, running vulnerability scans, or conducting simulated cyber attacks, regular security audits can address common weaknesses that increase your company’s susceptibility to becoming the victim of watering hole attacks. 

2. Employee Training

rain employees to recognize secure websites and be wary of unexpected pop-ups or redirects. Informed employees act as the first line of defense against many cyber threats, including watering hole incidents that prey on their trust in various websites. 

3. Use Security Software

Various software solutions help you automatically detect, prevent, and respond to the malicious activities seen in watering hole attacks. This includes ensuring all employee systems have updated antivirus and anti-malware software to detect and remove malicious files, monitoring network traffic, and securing endpoints like workstations, mobile devices, and servers via centralized tools.

4. Segment the Network

By dividing the internal network into distinct zones, you can ensure that if one section of the network is compromised, the attacker can’t easily move laterally to other sections. This segmentation limits the potential damage of a watering hole attack and can prevent the most critical systems from directly accessing compromised watering hole sites by restricting Internet access for those systems.

Real-World Implications of Watering Hole Attacks

When a watering hole attack occurs, it’s often challenging for security teams or law enforcement to identify the source and perpetrators of the attacks. These difficulties in tracing the origin of incidents stem from factors like:

• Skilled attackers use advanced techniques to mask their identities and activities. Techniques like routing through multiple proxy servers, using Tor, or exploiting botnets make it difficult to trace back activities to their origin.
• Watering hole attacks may leverage zero-day vulnerabilities (flaws not yet known to the software vendor or public). Because there’s no patch or detection method for these vulnerabilities, the attack can remain unnoticed for a significant period.
• Sophisticated attackers might intentionally leave “evidence” that points toward another entity and mislead investigators. 

Beyond the direct impact of watering hole attacks on end-user systems, here are some broader impacts to ponder.

Loss of Trust—Professionals might lose trust in an industry-specific website or similar websites. This can hinder communication and collaboration in the industry.

Economic Impact—Successful attacks can lead to theft of proprietary information and associated financial losses related to skewed competitive advantages or stock price fluctuations.

Operational Disruption—In cases where the watering hole attack leads to deeper network infiltration, there could be significant disruptions in the operations of the affected business.

Cost of Remediation—Detecting, addressing, and recovering from a watering hole attack is usually costly. Affected companies need to patch vulnerabilities, remove malicious software, possibly update or replace compromised hardware, and often improve their overall security infrastructure.

Reputational Damage—News of an attack, especially involving sensitive data compromise, can severely damage the reputation of the targeted organization or the industry as a whole.

Legal and Regulatory Repercussions—Depending on the nature of the data compromised and the jurisdiction, the affected organization might face legal and regulatory consequences, leading to fines or sanctions.

Prevention and Defense Mechanisms

You already have some insight into the high-level strategies that help mitigate these attacks, but here are some additional details on the kinds of prevention and defense mechanisms that are most helpful. 

Web Application Firewalls (WAFs)

A Web Application Firewall (WAF) is a specialized security system that filters, monitors, and blocks traffic between websites/ web apps and the Internet. Since WAFs are tailored for web applications, they offer a more precise level of inspection than traditional firewalls. WAFs identify malicious payloads in web traffic that might go unnoticed by other security measures. Lastly, WAFs protect websites that have known unpatched vulnerabilities by blocking attempts to exploit those vulnerabilities.

Keeping Software Updated

There’s no downplaying the enormous impact that effective patch management has on preventing and defending against watering hole attacks. The owners of websites who don’t want their popular sites used as a launchpad for watering hole attacks can stay on top of patch management so that cybercriminals can’t exploit common vulnerabilities and compromise their web property. Employee machines are less susceptible to malicious exploit kits if the software and operating system are kept up to date with the latest security patches. 

Incident Response Plans

An Incident Response Plan (IRP) is a well-defined approach that details the processes to follow when a cybersecurity incident like a watering hole attack occurs. In other words, these plans help your company handle a watering hole attack in a way that limits damage while reducing recovery time and costs. The IRP ensures that robust monitoring tools are in place to detect unusual activity on your network. Should an attacker compromise a website and attempt to insert malicious code or tools to target visitors, the monitoring tools can raise alerts with security teams who take swift action. 

Once a watering hole attack is detected, the IRP provides guidelines on immediate actions to contain the threat. This could involve temporarily blocking access to the compromised website across your IT environment or isolating affected user systems from the rest of the network. 

Conclusion

Watering hole attacks stand out as particularly insidious and cunning cyber threats in which adversaries adeptly exploit trusted digital spaces to ensnare unsuspecting victims. It is crucial for both organizations and individuals to be proactive in combating the threat of these attacks. 

Beyond the strategies and defense mechanisms outlined here, also consider the value of strengthening authentication. Website owners or admins can protect their accounts and their websites from being used in these attacks by using multi-factor authentication for logins. This simple action also protects the unsuspecting visitors to websites. 

At Kelvin Zero, we are building next-gen authentication and trust solutions to do exactly that. With our flagship solution, Multi-Pass, we are replacing passwords with enterprise-grade, phishing resistant passwordless MFA so our critical organizations can stay one step ahead of their attackers. 

Book a demo today to learn more about Multi-Pass and how Kelvin Zero can help your organization integrate trust throughout all of its operations.