Hackers seem to be exiting 2013 with a bang.
Last week, Target revealed that hackers had stolen data from 40 million credit and debit card shoppers who purchased items at its stores between Nov. 27 and Dec. 15.
That was the latest in a number of headlines that hackers and cybersecurity have made this year. Here are 2013's top cybersecurity stories.
NSA leaker Edward Snowden
When the U.S. government called out China for hacking the U.S., the Chinese government counterclaimed that it was the victim of U.S. attacks.
In June, an American, Edward Snowden, backed up China's claims. The former contractor for the National Security Agency told the South China Morning Post that the U.S. government had hacked Chinese telecommunication companies and a university, among other organizations.
The news came just days after President Barack Obama had met with Chinese President Xi Jinping in California and pressed him on cyberespionage.
Snowden also released confidential documents showing that the NSA was gathering phone and Internet records of Americans. Efforts are now underway to change how the agency gathers such information.
Is HealthCare.gov secure?
Health-care exchanges were immediately plagued by glitches when they launched in October. The federal site, HealthCare.gov, had technical troubles that led to far lower enrollment than expected. As problems persisted, many observers wondered if hackers were at least partly to blame.
The Department of Homeland Security disclosed last November there had been attempted hacks on HealthCare.gov.
Testifying before the House Homeland Security Committee on Nov. 13, Roberta Stempfley, acting assistant secretary of the department's office of cybersecurity and communications, said, "We have had a handful of reports from the Department of Health and Human Services. A number of about 16."
Homeland Security has not yet released updated numbers.
(Read more: New woes for Obamacare website—hackers)
Though the attacks were not successful, security experts told the House Committee on Science, Space and Technology on Nov. 19 that they were still concerned.
"These are things that could actually compromise sensitive information for people that have registered for the website and actually compromise the entire site itself," said David Kennedy, CEO of TrustedSec.