A widespread ad fraud campaign has been uncovered, involving hundreds of malicious apps on Google Play. These apps, which appeared as legitimate tools like fitness trackers and utility apps, tricked users into installing them. Once installed, they served full-screen video ads and attempted to steal sensitive data, including credit card details and login credentials. The campaign, named Vapor, affected millions of users globally and amassed over 60 million downloads. Cybersecurity researchers discovered that these apps used various evasion techniques to bypass Google’s security review processes.
Integral Ad Science (IAS) first reported the campaign in early 2024, identifying 180 apps involved in the fraud. These apps generated over 200 million fraudulent bid requests daily. Google has since removed the apps, but the campaign remains a significant concern due to the threat actors’ ability to avoid detection. The attackers used multiple developer accounts to distribute the apps and evade takedown efforts. Additionally, the apps used a technique called versioning, which involved updating the apps with malicious functionality after passing the initial security review.
Bitdefender later reported that the campaign had grown even larger, with 331 malicious apps identified. These apps were found to be particularly deceptive, hiding their icons and running in the background to display intrusive ads. Some apps even mimicked Google Voice to further disguise their malicious nature. The attackers exploited Android’s security vulnerabilities, particularly in versions 13 and above, to launch the apps without user interaction and keep them hidden. This allowed the fraudsters to maintain control over the device and continue their ad fraud activities.
While Google has removed the harmful apps, researchers warn that the threat may not be over. The attackers have shown the ability to adapt and reintroduce their fraud schemes through new apps. Users are advised to avoid installing unnecessary apps from unknown sources, check app permissions carefully, and regularly review their app list to spot suspicious installations. Despite these efforts, the Vapor campaign underscores the persistent risk of ad fraud on mobile platforms.
