The Societe Generale banker accused of operating a multibillion-dollar fraudulent trading scheme had only basic computing and programming skills -- a fact that deepens the mystery of how he managed to circumvent layers of highly sophisticated security software designed to prevent unauthorized activity.

On a copy of his resume that's widely circulating on the Internet, Jerome Kerviel lists Microsoft Office and Microsoft Visual Basic as his only IT-related skills. It also shows he performed some light programming work at Societe Generale that involved using Visual Basic to create macros for some of the French bank's trading and business applications.

While those skills might make Kerviel, a finance major, more computer-literate than many of his colleagues, they would hardly equip him for the kind of black hat hacking that would ordinarily be associated with a campaign of illicit, electronic trading that went undetected for months.

Kerviel's lack of advanced IT skills raises a pair of troubling possibilities. One is that Societe Generale's security systems were outdated or not properly maintained.

The other is that the junior-level trader was not working alone. Some reports have suggested that Kerviel used connections he made while working at Societe Generale's back office operations center to carry out the scheme -- which has cost the bank more than $7 billion.

Kerviel's overall resume hardly presents a portrait of a man bent on perpetrating the largest rogue trading campaign in banking history. It shows he holds a bachelor's degree in finance from the University of Nantes, teaches judo to kids, and likes sailing.

Whatever his motivations, Kerviel's actions sent shock waves through the world's banking system. There's speculation that Societe Generale's desperate attempts to unwind positions bought by Kerviel helped fuel a global market meltdown earlier this week that led the U.S. Federal Reserve to implement an emergency, 0.75% rate cut.

On Thursday, Societe Generale released a statement calling Kerviel's fraud "exceptional in size and nature." The bank said it has instituted dismissal procedures against Kerviel -- who's also facing criminal computer fraud and records falsification charges -- and that his supervisors would also be fired.

The bank also said it has instituted "additional control procedures" to prevent a reoccurrence of any rogue trading in the future, but did not provide specifics about the steps it would take.