Cyber criminals have become so adept that standard anti-virus software and firewalls cannot properly protect IT networks, according to an American expert.
Security specialist Tom Kellerman told The Straits Times that hackers now go to underground bazaars to buy purpose-built software that can bypass standard protections.
Developers of malicious software, or malware, have created stealthier and more intelligent strains that can stay undetected for a longer time so they can keep stealing data in the network, he noted.
"To maintain access without discovery, the malware can continuously rewrite its own code so as to evade detection," added Mr Kellerman, vice-president of software security firm Trend Micro.
He had served as Commissioner for Cyber Security during President Barack Obama's first term.
Mr Kellerman estimates cyber crime cost about US$300 billion (S$373 billion) globally last year, including money lost to intellectual property and credit card theft.
This is more than the US$285 billion involved in crimes related to narcotics globally.
The danger is that the cyber criminals will soon expand to other areas like cyber extortion, he warned, noting: "They can extort money from a company... (by threatening to) inject malware to damage its IT networks."
Mr Kellerman was responding to the spate of online attacks that have hit Singapore websites. Recently, a YouTube video posted by a hacker called "Anonymous" threatened to bring down Singapore's infrastructure in a show of protest against licensing regulations on online news sites.