SAN FRANCISCO -- Social media giant Twitter is among the latest U.S. companies to acknowledge that it is among a growing list of victims of Internet security attacks, saying that hackers may have gained access to information on 250,000 of its more than 200 million active users. And now, The Washington Post is joining the chorus, saying that it discovered that it was the target of a sophisticated cyberattack in 2011.
Twitter said a blog post on Friday it detected attempts to gain access to its user data earlier in the week. It shut down one attack moments after it was detected.
But Twitter discovered that the attackers may have stolen user names, email addresses and encrypted passwords belonging to 250,000 users they describe as "a very small percentage of our users." Nonetheless, the company reset the pilfered passwords and sent emails advising the affected users.
The online attack comes on the heels of recent hacks into the computer systems of U.S. media and technology companies, including The New York Times and The Wall Street Journal. Both U.S. newspapers reported this week that their computer systems had been infiltrated by China-based hackers, probably to monitor media coverage the Chinese government deems important.
On Friday, The Washington Post disclosed in an article published on its website that it was the target of a sophisticated cyberattack, which was discovered in 2011. The company's spokeswoman, Kris Coratti, didn't offer any details including the duration of the attack or the origins. But according to sources that the paper quoted, who it said spoke on condition of anonymity, the intruders gained access as early as 2008 or 2009.
The cyberattack was first reported by an independent cybersecurity blog on Friday.
One expert said that the Twitter hack probably happened after an employee's home or work computer was compromised through vulnerabilities in Java, a commonly used computing language whose weaknesses have been well publicized.