A growing menace: flubots, phishing, and network failures


As we buy more and more stuff online, text messages like “track your order at this link: http://….” are accepted as the norm. You’ve probably clicked one or two of those links yourself, right? And why shouldn’t you?

It sounds innocent enough, but it might not be. That simple SMS could be the vehicle for a flubot attack. Clicking on the link could cause massive headaches for mobile operators and the industry as a whole. Increases in mobile malware pose a real threat to the telecommunications infrastructure. The implications are serious – both operationally and commercially.

How does a flubot work?

Successful flubots typically build-out botnets that can cripple telecoms networks by generating large volumes of voice calls and SMS messages, as well as mobile data traffic targeted at specific websites and servers – a DDOS (distributed denial-of-service) attack.

Flubots work like this: distribution systems send personalized SMS messages containing links that look genuine, making them difficult to detect and prevent. Clicking on the link triggers a malware download which can then take over the device and send a similar message to contacts; while also initiating DDOS attacks. The malware can also start phishing for bank details, perform identity theft, or make purchases.

How much damage can a flubot cause?

Flubot attacks are happening at scale. In October 21 alone, Sinch’s anti-spam platform detected and blocked more than 1.6 million malicious URLs, while one mobile operator recently reported 10,000 customers had been infected by flubot malware. That attack generated 3,000 messages (both national and international) per customer per day, causing SMS traffic between network operators to soar tenfold. In another attack, 5,000 infected devices called a target number every 10 minutes, resulting in about 30,000 calls per hour.

In the graphic below, you can see the evolution of a flubot attack on a medium-sized MNO in the APAC region. Sinch anti-fraud systems captured over 100K fraudulent SMS messages before customers realized anything had happened. This case is very similar…

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