Malvertising, also known as malicious advertising, refers to an attack in which cybercriminals inject malicious code into legitimate online advertising networks, redirecting users to malicious websites, with the goal of spreading malware.

These malicious ads can exploit vulnerabilities in the user’s browser, operating system, or even in plugins like Flash or Java, leading to serious security breaches, data theft, or further compromises of the user’s system.

How Malvertising Works

Malvertising typically involves three primary components: the attacker (who creates the malicious ad), the ad networks (which distribute the ad), and the target user (who views or interacts with the ad). The process often unfolds in the following steps:

  1. Ad Creation: Cybercriminals design a deceptive or infected ad, which may appear as a banner, pop-up, or video on a legitimate website. The ad may contain hidden scripts or malicious links that can download malware directly to a user’s device when clicked, or even without interaction (a technique known as “drive-by downloads”).
  2. Ad Distribution: These malicious ads are often distributed through legitimate ad networks, which aggregate inventory from a variety of publishers. Attackers exploit these networks by purchasing ad space, similar to how any advertiser would, but with the intention of spreading malware. These networks typically lack the ability to fully inspect every ad or may fail to spot the malicious content in time.
  3. User Interaction: Once the ad is served to an end-user, the malicious payload can either be activated immediately (in the case of drive-by downloads) or after the user clicks on the ad. In some cases, the malware can redirect the user to a fake website that looks like a legitimate service, tricking the user into providing personal information, downloading malicious files, or running malware themselves.

Common Types of Malvertising

  • Exploit Kits: Malvertising is often used to deliver exploit kits, which are tools designed to take advantage of security vulnerabilities in software that has not been updated with the latest patches. These kits automatically probe the system for known weaknesses (such as outdated browser plugins) and deploy malware when a vulnerability is found.
  • Ransomware: Some malvertisements can serve as the initial vector for ransomware attacks. Once the ransomware is installed, it can encrypt files on the user’s device and demand payment for decryption.
  • Ad Fraud: Another form of malvertising is ad fraud, where attackers use fake or hijacked ad networks to generate revenue by manipulating the way advertisements are served. This can also contribute to phishing schemes and credential theft.
  • Cryptojacking: Malvertising can also be used to distribute scripts that hijack a user’s computing power to mine cryptocurrency. This type of attack is often designed to run silently in the background, consuming CPU resources and causing performance issues without the user’s knowledge.

Risks and Impact

The risks of malvertising are significant and can have far-reaching consequences for individuals, businesses, and the broader internet ecosystem. Some of the potential impacts include:

  • Data Breaches: Malvertising can be used to steal sensitive information, including login credentials, banking details, and personal data, which can then be used for identity theft or sold on the dark web.
  • System Compromise: Malware delivered via malvertising can result in system infections, which can give attackers remote access to a user’s device. This could lead to further attacks, including the installation of additional malicious software or the exfiltration of private files.
  • Financial Loss: Ransomware and fraud-related malvertising attacks can lead to significant financial losses, either through direct extortion or the theft of funds.
  • Damage to Brand Reputation: Websites or ad networks that inadvertently serve malvertising ads risk damaging their reputations and losing trust among their users. This is especially true for large platforms or well-known content providers who may become associated with malicious ads.

Mitigating the Threat of Malvertising

Defending against malvertising requires a combination of technical measures, awareness, and vigilance. Some effective strategies include:

  • Ad-blocking Software: Using ad blockers or security extensions in web browsers can help prevent malicious ads from appearing in the first place.
  • Up-to-date Software: Ensuring that browsers, operating systems, and plugins are always updated with the latest security patches is crucial in preventing exploit kits from taking advantage of known vulnerabilities.
  • Website Security: Website owners and advertisers should ensure they work with trusted ad networks and take steps to audit the ads served on their platforms regularly.
  • Education and Awareness: Users must be educated about the dangers of clicking on suspicious ads or downloading content from untrusted sources.

In conclusion, malvertising represents a growing and evolving threat within the cybersecurity landscape. As cybercriminals continue to exploit the trust users place in online advertising, both individuals and organizations must remain vigilant in order to mitigate the risks associated with these malicious campaigns.

About BlackFog

BlackFog is the leader in on-device data privacy, data security and ransomware prevention. Our behavioral analysis and anti data exfiltration (ADX) technology stops hackers before they even get started. Our cyberthreat prevention software prevents ransomware, spyware, malware, phishing, unauthorized data collection and profiling and mitigates the risks associated with data breaches and insider threats. BlackFog blocks threats across mobile and desktop endpoints, protecting organizations data and privacy, and strengthening regulatory compliance.