Google warns of deadly manual account hijacking attacks

Maximum damage, difficult recovery

If an attacker compromises an online account what damage can they do and does the user wrest back control?

A new Google analysis of manual (as opposed to automated) account takeovers on its own services between 2011 and 2014 suggests that getting a hijacked account back is often a painful process that happens only after considerable damage has been done.

Manual attacks get to work on a compromised Gmail victims account very rapidly, within 30 minutes in many cases, while trawling through the victim's email history for banking details and other valuable data usually took no longer than between minutes.

Attackers - most of whom come from China, Ivory Coast, Malaysia, Nigeria, and South Africa - also harvest close contacts to launch secondary attacks, in which case exploitation time rises a bit.

Google's first takeaway is that these attacks are launched using the same phishing attacks used to pivot almost every Internet crime in existence, which people continue to fall for in large numbers.

The best manual phishing attacks achieve a 45 percent success rate, although a typical average appeared to be around 13.7 percent. Where attacks were carried out from hijacked accounts (and appeared to come from trusted subjects), targets were 36 times more likely to fall victim.

The long and the short of this is that if a manual attacker gets into your Google account you're probably not going to know about it until it's too late.

Getting a hijacked account back can be difficult if no secondary email address or (better still) mobile phone number has been set up to verify identity although even that assumes the hijackers don't alter that data to delay this process (which in some cases they have although that carries risks for them).

For half of victims the average time was up to 13 hours, which implies that a smaller group will take much longer. Luckily, manual account hijacks remains very rare, as few as 9 incidents per million, Google said.

So, in summary, Google seems to be underlining that while manual account attacks represent only a tiny percentage of online account takeovers when they strike their effects are worse and recovery more difficult.

The best defence against account takeover of any kind on Google's services is 2-Step Verification, a security layer that locks access down to trusted computers and adds a second factor to the authentication process, usually a mobile phone.

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