As 2009 wound down, I wrote a piece questioning whether China, which was grabbing up oil properties voraciously, would buy "all the world's oil." Little did I know that people in that country were sopping up information in the dead of night to gain a leg up on Western competitors.

Indeed, it's come to light that computer hackers located in China have violated the computers of Big Oil and oilfield-services companies. It seems they've hit the likes of ExxonMobil (NYSE: XOM), Royal Dutch Shell (NYSE: RDS-A), and BP (NYSE: BP), according to McAfee, a California-based cybersecurity firm. The hackers also have hit the computers of oilfield services provider Baker Hughes (NYSE: BHI).

The covert activities apparently were conducted between 9 a.m. and 5 p.m. Beijing time (13 hours ahead of New York City), a schedule that was at least partially responsible for McAfee dubbing them "Night Dragon." The clandestine efforts were intended to gain access to the companies' "crown jewels," such as specifics on deals, legal information, and financial data. The raids' targets also included topographical maps, which are typically worth millions of dollars.

The hackers reportedly had the opportunity to access the data undetected for at least a year. Some investigators peg the start of the shenanigans in November 2009, while others believe it actually began in 2008.

In addition to the companies named above, the hackers also made their way into the computers of Marathon Oil (NYSE: MRO) and ConocoPhillips (NYSE: COP). Once they uncovered these attacks, the companies did not report them to regulators. Also, following the hacking discovery, it appears that Baker Hughes felt it unnecessary to inform its investors, a failure that could saddle it with a legal liability.

The hackers apparently used a "spearfishing" approach, wherein employees of a target company were sent emails that appeared to be from their colleagues. Once opened, the doctored email links headed for infected sites or unleashed attachments that installed backdoors on the computers. Those involved in the operation were then able to lift specific files, circumventing protection including firewalls.

As McAfee's report noted, the "unsophisticated" hacking techniques employed were representative of espionage operations typically conducted with the knowledge of the Chinese government. According to a WikiLeaks cable, Google (Nasdaq: GOOG) announced late last year that, under the direction of high-level Chinese officials, the company's computers in China had been compromised.  

With Big Oil competing worldwide with Chinese companies, the members of the group, from Exxon down, will clearly become more compelling for Foolish investors, given a leveling of the playing field.