New Delhi: If an ad pops up every time you open Whatsapp, then you have fallen victim to virus named Agent Smith. Also Read - International Women's Day: Google Honours History of Firsts Achieved by Women Through Video Doodle

Agent Smith, an Android malware, has affected 25 million phones across the world. Also Read - Twitter Announces New Feature That Would Let Users Charge Followers, Netizens React

According to reports, over 1.5 crore devices from India have been hit while in the US, the number has been pitched at 3 lakh. Also Read - WhatsApp's Fate Hangs in Balance as New Rules Require to Identify Originator of a Message | EXPLAINED

The malware has been rightly named ‘Agent Smith’ due to its ability to attack an Android device unnoticed. The malware only displays advertisements, disguises itself as a Google-related application, and automatically replaces installed apps with malicious versions without dropping hints to android device users.

As per the information provided by Check Point, an Israeli security firm, the Agent Smith malware spreads via third-party app stores namely 9Apps.

The third-party app stores are mostly used by Indian Andriod users to download modified versions of apps. Through these apps, the malware injects itself on phones. According to reports, the malware primarily hides in sex-related, games and photography apps. Popular apps such as Whatsapp and Flipkart have not been spared either as the malware has injected its code into these too.

A user hit by the Agent Smith virus sees more ads on their phones.

What is posing a challenge is detecting Agent Smith on an affected phone. Mobile Threat experts are of the view that common Android users can’t detect the virus threat on their own. However, in a warning, they say that users must download from trusted apps that reduce the risk of such viruses spreading on phones. Apps like 9apps lack security measures and fail to block adware.

Further, Google has been informed about the malware. Following which, the company has removed apps that were affected by it. “So far, the primary victims are based in India though other Asian countries such as Pakistan and Bangladesh have also been impacted. Check Point has worked closely with Google and at the time of publishing, no malicious apps remain on the Play Store,” India Today quotes Google as saying.

All said, Andriod users are advised against using third-party app stores like 9Apps. If they feel that their phone has been affected by the malware, users must delete data of popular apps by going into settings and later, reinstalling them. They may also resort to doing a factory reset.