The attacks can be difficult to trace, as hackers route their probes through worldwide networks of other hacked computers known as botnets. Up to 25 percent of computers infected with botnet code are in enterprise networks, said Rik Ferguson, senior security adviser for Trend Micro.
Because commands to those bots are encrypted, it can be difficult for investigators to identify who is behind the attacks, he said.
"It's a shifting landscape all the time," Ferguson said. "The more success that law enforcement and the security industry had, the more we oblige the criminal element to innovate and find new ways to do things."
The attacks against Google were low-volume operations, which means it is trivial for the perpetrators to cover their tracks, said Scott Borg, director and chief economist for the U.S. Cyber Consequences Unit, an independent nonprofit research institute that assesses the impact of cyberattacks.
"Almost anyone who is willing to go to enough trouble can obtain anonymous Internet access, even in China," Borg said. "It is possible that the senior Chinese leaders are right now trying to find out who did what."
Even with stronger security, there will always be a small window of opportunity for hackers.
While many software companies now create patches faster for vulnerable software, there still is a gap of time in between when the vulnerability is found and when the fix is ready. If a vulnerability is already being exploited when it is publicly disclosed and there is no patch, it is known as a zero-day attack, the most dangerous type of problem.
It's doubtful there will be a day when software will be free of vulnerabilities said Andre' M. DiMino, co-founder of Shadowserver, a volunteer-run organization that tracks botnets.
"As long as there are unpatched applications and operating systems, poorly secured networks and Web sites, as well as users not taking basic precautions, we'll continue to see system compromises," DiMino said.
Google's revelations are further affirmation of what other analysts have said is an uptick in industrial espionage using computers.
"Let's be honest: If you can hack Google, there must be a lot of technology companies that should be similarly worried about their systems," said Tom Watson, a Labour Member of Parliament for West Bromich East.
Watson put forth an early-day motion in the U.K.'s Parliament on Wednesday, a motion that other U.K. lawmakers can sign on to show their support for Google's decision to stop censoring search engine results in China.