Beware of new malware that steal browser cookies, allow hackers remotely control your web activity

Computer security software major Kaspersky has warned against two new Android malware modifications which together can steal cookies collected by the browser and app of popular social networking sites and then allow the thieves to discreetly gain control of the victim's account in order to send various ill-intentioned content.

Cookies are small pieces of data collected by websites to track users' activity online in an effort to create personalised experiences in the future. While they're often perceived as a harmless nuisance, they can, in the wrong hands, pose a security risk.

That's because, when websites store these cookies, they use a unique session ID that identifies the user in the future without requiring a password or login. Once in possession of a user's ID, tricksters can fool the websites into thinking they are in fact the victim and take control of the latter's account.

And that's exactly what these cookie thieves did by developing Trojans with similar coding controlled by the same command and control (C & C) server.

The first Trojan acquires root rights on the victim's device, which allows the thieves to transfer Facebook's cookies to their own servers.

However, oftentimes, simply having the ID number isn't enough to take control of another's account. Some websites have security measures in place that prevents suspicious log-in attempts, say, for example, a user previously active in Chicago attempts to log-in from Bali just a few minutes later.

That's where the second Trojan comes in. This malicious app can run a proxy server on a victim's device to bypass security measures, gaining access without arising suspicion. From there, the criminals can pose as the victim and take control of their social networking account to distribute undesirable content.

While the ultimate aim of the cookie thieves remains unknown, a page uncovered on the same C & C server could provide a hint: the page advertises services for distributing spam on social networks and messengers. In other words, the thieves may be looking for account access as a way to launch widespread spam and phishing attacks.

"By combining two attacks, the cookie thieves have discovered a way to gain control over their victims' account without arising suspicions. While this is a relatively new threat -- so far, only about 1,000 individuals have been targeted -- that number is growing and will most likely continue to do so, particularly since it's so hard for websites to detect," said malware analyst Igor Golovin.

"Even though we typically don't pay attention to cookies when we're surfing the web, they're still another means of processing our personal information, and anytime data about us is collected online, we need to pay attention," Golovin added.

Here's how you can save yourself from becoming a victim of cookie theft, according to Kaspersky experts:

- Block third-party cookie access on your phone's web browser and only let your data be saved until you quit the browser

- Periodically clear your cookies

- Use a reliable security solution that includes a private browsing feature, which prevents websites from collecting information about your activity online.