Look, you’re not perfect. Maybe you’re behind on your bills, or you left a pile of dishes in the sink this morning, or (like this writer) you once ran over a rabbit by accident. But at least your Twitter account isn't spewing hateful content, right?
Twitter Counter, a popular third-party app for keeping track of followers, was the victim of a hack that made its users spout jingoistic nonsense full of Nazi symbols. While you may not have that exact app installed, you may be entrusting your Twitter account to similar software.
Computer support site Bleeping Computer summed up the whole incident pretty well. A number of Twitter users — both everyday Joes and high-profile targets like security blogger Graham Cluley — seemed to take a sudden and rather violent interest in the ongoing dispute between Turkey and the Netherlands.
Cluley and other compromised users suddenly started spouting Turkish nationalist propaganda, complete with swastikas and hashtags that called both the Netherlands and Germany “Nazis.” There was also a video link to a speech by President Erdogan.
What you should do
If you have Twitter Counter, you may want to uninstall it. (Although at this point, the damage has been done, and Twitter Counter is unlikely to fall for the same hack twice.)
Beyond that, there’s unfortunately no perfect defense against app exploits, save for eliminating every single third-party Twitter app you use. That’s your call, although some connections (like PlayStation, LinkedIn, Google, and so forth) are pretty useful.
At the very least, you should check which Twitter apps you have installed by going to your Twitter account and selecting the Apps section. If you see anything that requires read and write access, it could tweet on your behalf if it gets hacked. Revoke access if you wish -- you should to apps you don’t use on a regular basis. Older, disused apps are just a security risk waiting to be exploited.
Also, if you're the only person using a specific Twitter account, enable two-factor authentication (2FA). That might prevent the sort of account hijacking we saw in this case. Unfortunately, many commercial Twitter accounts have multiple humans controlling them, and implementing 2FA in those instances is not always practical.
How they did it
The same hackers (or hackers with very similar political agendas) also compromised some high-profile Dutch websites and replaced the text with some moralizing and vaguely threatening content. Among other things, the hackers accused the rest of Europe of colonialism, racism, fascism and a “Crusade mentality.”
These hackers did not compromise hundreds of different Twitter accounts individually. Rather, they took advantage of one weak link in a long daisy-chain of apps.
Every compromised account used a paid service called Twitter Counter, which is a fairly simple plugin that keeps track of followers. However, the app requires that the account holder grant the app both read and write permissions in Twitter by giving it the password to the account.
This isn’t uncommon; many Twitter plug-ins request the same level of access. But by compromising Twitter Counter, the Turkish hackers were able to use its read/write permissions to write tweets for its users.