Nightly News | April 23, 2013
>>> there was a sudden flurry today over an urgent story reported by the associated press on their twitter feed. it was about an attack on the white house , injures to the president. it was false. it was enough to scare people and move the stock market . it was a hack, the latest in a series of high profile hacks that have companies scrambling and people wondering sometimes what's real. our senior investigative correspondent lisa myers is with us with more on this from washington. lisa, good evening.
>> reporter: good evening, brian. with the country already on edge and social media having gone mainstream, all it took was 71 characters to send the stock market into free fall. it all began about 1:07 this afternoon with this tweet from the associated press.
breaking: two explosions in the white house and barack obama is injured. the message went to ap 's 1.9 million twitter followers and spread like a virus. retweeted almost 5,000 times within a minute. but it was a fake. ap 's account had been hacked.
>> it partly explains the unusual activity in the dow.
>> reporter: the dow began plunging and within three minutes dropped more than 140 points.
>> you looked around the floor. you saw people running, people upset. not sure what was going on. just watching this market trade lower.
>> reporter: automatic trading programs kicked in.
>> human beings weren't making these trades. these were computers, algorithms to scan the headlines and find negative or positive words and help companies profit as a result.
>> reporter: the ap corporate account tweeted it was bogus and suspended the twitter page.
>> i can say that the president is fine. i was just with him.
>> reporter: the syrian electronic army took credit for the hacking as well as hacking into cbs' " 60 minutes " twitter account over the weekend. the nbc news twitter account was hacked two years ago days before the anniversary of 9/11. and a false tweet was put out about an attack and hijacking. today the stock market recovered, but with a new sense of just how vulnerable and jittery we are.
>> to have that kind of impact from a 140-character tweet that actually unnerves the entire global system beginning with the stock market , that's actually quite significant.
>> reporter: an s.e.c. official says the stock exchanges will know who profited and who lost from today's gyration. the secret service says it's aware of the incident and will monitor and follow up appropriately.
>> unbelievable turn of events today. lisa, thanks.