The profile of attacks on two US state voter registration systems this summer presented in an FBI "Flash" memo suggests that the states were hit by a fairly typical sort of intrusion. But an Arizona official said that the Federal Bureau of Investigation had attributed an attack that succeeded only in capturing a single user's login credentials to Russian hackers and rated the threat from the attack as an "eight on a scale of ten" in severity. An Illinois state official characterized the more successful attack on that state's system as "highly sophisticated" based on information from the FBI.
Arizona Secretary of State Office Communications Director Matt Roberts told the Post's Ellen Nakashima that the FBI had alerted Arizona officials in June of an attack by Russians, though the FBI did not state whether they were state-sponsored or criminal hackers. The attack did not gain access to any state or county voter registration system, but the username and password of a single election official was stolen. Roberts did not respond to requests from Ars for clarification on the timeline and other details of the attack.
Based on the details provided by Roberts to the Post, it's not clear if the Arizona incident was one of the two referred to in the FBI "Flash" published this month. The FBI has not responded to questions about the memorandum on the attacks first published publicly by Yahoo News' Michael Isikoff, but a SQL injection attack wouldn't seem to be the likely culprit for stealing a single username and password. It's more likely that the Gila County election official whose credentials were stolen was the victim of a phishing attack or malware.