Hackers attacked computers in the Israel's Civil Administration for the West Bank, the Israeli computer security firm Seculert has reported.

Company officials believe the same group that hacked into Israel Police and other government systems in 2012 was behind the latest attack, which was detected on January 15. It affected about 15 computers in various agencies, some of them private companies not involved in security.

Seculert described the incident as a so-called spear-phishing attack. This is how it penetrated the system: A PDF file infected with a program called Xtreme RAT was attached to an email that was addressed to specific individuals in a number of organizations. Xtreme RAT is a “Trojan Horse” that enables the sender to gain remote access to affected computers and is generally used for espionage.

The emails were sent from the email address Shabakreport@gmail.com and were titled “Shabak Report,” in an effort to emulate emails from the Shin Bet security service, the acronym of which in Hebrew is Shabak. In some cases a genuine Shin Bet document - one that can be downloaded from the agency’s website - was also attached to the email.

Seculert’s chief technology officer, Aviv Raff, said the attack was apparently carried out by Palestinian activists in the Gaza Strip, either for ideological reasons or for money. “The modus operandi was identical to the previous attack,” Raff said, adding that the group behind the previous attack has been active for at least two years. He said that as soon as a single email from the group was received in the latest attack, the company monitored server traffic and located the various sources of the transmission.

The group made headlines in 2012 for its hacker attack, which was dubbed “the Benny Gantz virus” because the attackers made their emails appear to have been sent by the chief of staff of the Israel Defense Forces. The IDF Spokesman’s Office said the matter is under investigation.