Iranian Intelligence Minister Heydar Moslehi announced today the arrests of multiple people he described as "nuclear spies."
Moslehi told the Mehr News Agency of the arrests, but offered no further details. The arrests follow reports that the Stuxnet worm infected computers belonging to staff at the Bushehr nuclear power plant, where it reportedly did no damage.
It is unclear if the arrests are related to the worm, but Moslehi expressed confidence the country could repel cyber-attacks by foreign intelligence agencies.
"We are always facing destructive activities by these [espionage] services, and, of course, we have arrested a number of nuclear spies to block the enemy's destructive moves," Moslehi reportedly said.
Iran has been the site of many of the infections of Stuxnet, which has been traced as far back as June 2009. The worm was discovered a year later by security vendor VirusBlokAda when it was seen exploiting a Windows zero-day vulnerability. In the ensuing months, details of its functionality have continued to emerge, prompting some to call it one of the most sophisticated pieces of malware in the wild.
The worm targets industrial control systems, a fact Eric Chien, technical director of Symantec Security Response, said Thursday raises its threat level.
"Everything that we've looked at in the past ... really is nothing compared to Stuxnet, because the things that we look at are attacking virtual assets, like someone posting [something] to your Facebook wall that you didn't want them to, or things like someone stealing an individual's credit card number," said Chien, who co-authored a paper on Stuxnet. "When we're talking about Stuxnet, we're talking about national critical infrastructure. ... The code to actually sabotage the industrial control systems is actually in Stuxnet."
Though no definite link to an author has been established, speculation has abounded that the worm was created by a government for the purpose of sabotage.
Some have speculated that the worm's code provides clues to its origin. Contained within the code is the word "myrtus," which is considered by some to be an allusion to the Old Testament Book of Esther, which contains a story of a thwarted attempt to destroy the Jews. Myrtus is also known as myrtle, the Hebrew word for which is Hadassah-the birth name of Esther.
Also contained within the code, however, is the word guava, and Myrtus is the botanical family of the guava plant.
Other potential evidence rests with Stuxnet's main installer, which among other things checks the date and version number of the compromised computer; decrypts, creates and installs the rootkit files and registry keys; and injects itself into the services.exe process to infect removable devices.
According to a paper (PDF) on Stuxnet by Symantec: "Export 16 [main installer] first checks that the configuration data is valid, after that it checks the value 'NTVDM TRACE' in the following registry key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\MS-DOS Emulation.
"If this value is equal to 19790509 the threat will exit," the paper states. "This is thought to be an infection marker or a 'do not in??Ãfect' marker. If this is set correctly infection will not occur. The value appears to be a date of May 9, 1979. ... According to Wikipedia, Habib Elghanian was executed by a firing squad in Tehran, sending shock waves through the closely knit Iranian Jewish community. He was the first Jew and one of the first civilians to be executed by the new Islamic government."
Chien cautioned, however, against reading too much into the findings, as the worm's author may have simply placed those things there to throw researchers off course.