Notorious hacker group Lizard Squad has apparently struck again - just a day after it allegedly hacked the website of Malaysia Airlines.
It has claimed responsibility through its Twitter account for causing the hour-long blackout of social media platforms Facebook and Instagram, as well as other popular sites on Tuesday. But Facebook said that an internal software networking error was to blame.
Just who are these cyber attackers? Here are five things to know about the group:
1. Known for making DDoS attacks
A distributed denial-of-service or DDoS attack is an attempt to make an online service unavailable for its users through overwhelming it with traffic from multiple sources.
Lizard Squad inflicted its first DDoS attack last August, when they took down the servers of online game League Of Legends. This was followed by more attacks on shooting game Destiny, as well as gaming platforms Twitch, Xbox Live and the PlayStation Network.
The group also claimed responsibility for an attack that took North Korea's Internet offline on Dec 22, 2014.
2. Hacking of websites
Lizard Squad first hacked American gaming and media streaming website Machinima Inc. on Dec 2, 2014, defacing its homepage with characters in the shape of a lizard (from which the group's name is derived).
On Monday, it turned its attention to the website of Malaysia Airlines. Visitors were directed to another page showing a photo of a monocle- and tuxedo-wearing lizard and messages that read "404 - Plane Not Found" and "Hacked by Lizard Squad - Official Cyber Caliphate".
Despite Malaysia Airlines stating that its users data was not compromised, tweets by the group claimed otherwise. It has also threatened MAS with a data dump.
An image was also posted which had a list of travel itinerary receipts, including an urgent flight reservation for Malaysia's International Trade and Industry Minister Datuk Seri Mustapa Mohamed.
3. Claims of ISIS-links and bomb threat tweet
On Aug 24, 2014, American Airlines flight 362 with Sony Online Entertainment president John Smedly on board was grounded when Lizard Squad tweeted a bomb threat.
The group has been linked to the Islamic State of Syria and Iraq (ISIS) in the past after mentioning ISIS during its attacks.
A tweet made on the same day as the bomb threat read: "Today we planted the ISIS flag on @Sony's servers #ISIS #jihad", while reports suggest that it is being investigated by the FBI
4. Two purported group members identified
"Member 1", a 16-year-old Finnish teenager named Julius Kivimäki, has been interviewed by the BBC, while "Member 2" is Vinnie Omari, a 22-year-old from the UK.
Kivimäki had been arrested in October 2013 under suspicion of running an illegal bot network, and was believed to have been found to have more than 3,000 stolen credit cards.
Omari, whom some believe is an alias, has been connected to another hacking group called Null Consolidated, which was responsible for a separate website attack on Solomid, which publishes strategy game guides for League Of Legends.
5. Heavy use of Twitter
Outside of its hacking activities, the group relies heavily on its Twitter account Lizard Squad (@LizardMafia) to relay taunts of its hack victims and promises of upcoming attacks.
The account was created in 2011 but became active only last August.
Sources: BBC, Forbes, Twitter, Daily Mail, International Business Times, KrebsonSecurity.com, Heavy.com