That finding comes from a new study released on Monday by Verizon, which reviewed 200 PCI assessments which it conducted as a PCI qualified security assessor (QSA) in 2008 and 2009.
By contrasting PCI assessment information with post-breach details, Verizon found that the top techniques attackers use to steal payment card data were malware and hacking (25%), SQL injections (24%), and by exploiting weak passwords or unchanged default passwords (21%).
On a related note, the study found that attackers are most likely to target the three aspects of PCI with which companies most struggle. "Of the 12 requirements that constitute the PCI DSS, three of them -- protect stored data, track and monitor access to network resources and cardholder data, and regularly test security systems and processes -- cover areas that are most vulnerable to security breaches," according to Verizon. "However, those three requirements are also the same ones that companies struggle the most to meet for PCI compliance."
Interestingly, only 22% of organizations comply with PCI at the time of their initial assessment, said Verizon. These tended to be organizations that were "veterans of the validation process" or which were lucky enough to have numerous "not applicable" requirements.
Verizon found that at the initial assessment phase, the average organization did have 81% of the roughly 250 required PCI testing procedures in place, and only 10% of organizations failed more than half of the tests. According to Verizon, "this seems to suggest a 'last mile' kind of problem with respect to the PCI DSS," though it's unclear whether this relates to inherent difficulty, or rather organizations focusing "on the majority they feel are most beneficial."
The PCI standard, backed by American Express, Discover Financial Services, JCB International, MasterCard Worldwide, and Visa, aims to improve credit and debit card security. But PCI compliance has been a tough sell for many merchants, and many smaller businesses still don't understand many PCI requirements.
Indeed, according to a survey conducted earlier this year of U.K. businesses by market research firm Redshift Research on behalf of Tripwire, 89% of U.K. companies hadn't undergone the required auditing and certification process, and 35% said they still didn't fully understand PCI.