Twitter and the Washington Post are the latest media companies to reveal that they, too, were victims of cyber attacks.
Last week, The New York Times and The Wall Street Journal reported cyberattacks on their computer systems and both organizations reported the attacks appeared to be the work of Chinese hackers.
(Read More: Hackers in China Attacked The Times for Last 4 Months )
The Post said that its attack also was likely the work of Chinese hackers, and that the attacks — which were discovered in 2011 — likely compromised some administrative passwords, giving the criminals access to the Post's computer systems before the computers were taken offline.
The attack on Twitter's system occurred on Friday and while the company was able to quickly shut down the "live attack," the attackers may have been able to access information for about 250,000 Twitter users, the company said in a blog post.
The criminals were able to access usernames, email, addresses, and encrypted passwords.
(Read More: New Malware Attacks Smartphone, Computer to Eavesdrop )
"Though only a very small percentage of our users were potentially affected by this attack, we encourage all users to take this opportunity to ensure that they are following good password hygiene, on Twitter and elsewhere on the Internet," the company stated in its post.
The company urged users to use a password that was at least 10 characters long and a mixture of upper and lower case letters, numbers, and symbols.
(Read More: How to Protect Your Devices From New Hack Threat )