App developers often include ads on their applications to increase revenue. These ads feature enticing titles or blurbs to surge more user hits. Typically, clicking these ads either prompt users to download an app or be redirected to a web page. However, cybercriminals who never run out of new ways to spread their deeds, could also use this as a venue to steal user information.
We recently spotted a fraudulent website which is pushed by ads found in multiple Android apps. (Some of these apps were downloaded from the Google Play store, while others were found from third-party stores.) These ads use popular brands as hooks like “iPhone 5” and “Samsung Galaxy Note II” and supposedly selling these items for a ridiculously low price. Once users click the ad, it will lead them to a website which shows many means to buy the said phones.
Figure 1. Ad for Samsung Galaxy Note II
Figure 2. Ad for iPhone 5
In reality, these sites are just scam sites that try to defraud users out of their money. They do not actually sell the devices they are promoting.
Figure 3. Fraudulent website advertising Samsung Galaxy Note II
Figure 4. Fraud website with iPhone 5 ad
These ads are being delivered by a large, mainstream ad network, which claims to be used by more than 90,000 apps. While this attack is currently limited to Chinese users, because of the large number of apps on this particular ad network it is possible that similar attacks will be delivered to other users in the future.
Last March, we blogged about Google’s decision to remove apps that block ads and the potential risks this may pose on unsuspecting users. No doubt the insufficient audit of ads on the Android platform may lead to more fraud, phishing attacks or even malware distribution. We recommend ad providers to provide more powerful audit mechanisms to protect users from attacks leveraging ads.
Trend Micro protects users from this attack by blocking the said malicious website. We also advise Android users to be cautious in clicking ads on their devices as this may potentially lead to information and identity theft. For better protection of your devices, users should also be wary of other mobile threats like malicious URLs and mobile phishing sites.
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