CAPTCHAs, those squiggly and frustrating puzzles that many Web sites require users to solve before registering or leaving comments, are designed to block automated activity and deter spammers. But for some Russian-language forums that cater to spammers and other miscreants, CAPTCHAs may also be part of a vetting process designed to frustrate foreigners and outsiders.

“Verified,” one of the longest-running Russian-language forums dedicated to Internet scammers of all stripes, uses various methods to check that users aren’t just casual lurkers or law enforcement. It recently began using CAPTCHAs that quiz users about random bits of Russian culture when they register or log in.

Consider this CAPTCHA, from Verified: “Введите пропущенное число ‘… мгнoвeний вeсны.'” That translates to, “Enter the missing number ‘__ moments of spring.'”

But it may not be so simple to decipher “мгнoвeний вeсны,” the “moments of spring” bit. One use of cultural CAPTCHA is to frustrate non-native speakers who are trying to browse forums using tools like Google translate. For example, Google translates мгнoвeний вeсны to the transliteration “mgnoveny vesny.” The answer to this CAPTCHA is “17,” as in Seventeen Moments of Spring, a 1973 Russian television mini-series that was enormously popular during the Soviet Union era, but which is probably unknown to most Westerners.

Although these cultural CAPTCHAs may not stop those determined to break them, cultural CAPTCHAs are an interesting approach to blocking unawanted users. Most CAPTCHA systems can be trivially broken because they merely require users to repeat numbers and letters. Some CAPTCHAs ask the visitor to solve math or logic puzzles, but these questions can be answered by anyone with a grade school grasp of math.

Spammers tend to rely on commercial, human-powered CAPTCHA solving services, which automate the solving of CAPTCHAs with the help of low-paid workers in China, India and Eastern Europe who earn pennies per hour deciphering the puzzles. CAPTCHAs that bombard workers at these automated facilities with a range of cultural questions might frustrate these low-paid workers, but the challenges likely would be more frustrating (not to mention alienating and offensive) to legitimate users who are unfamiliar with the targeted culture.

In many ways, cultural CAPTCHAs seem to be uniquely suited for small, homogeneous and restricted online communities. I would not be surprised to see their use, variety and complexity increase throughout the criminal underground, which is constantly trying to combat the leakage of forum data that results when authorized members have their passwords lost or stolen.

Tags: 17 Moments of Spring, CAPTCHA, Verified.ms