BERLIN (Reuters) – The German parliament was the target of fresh cyber attacks in January that attempted to piggy-back on an Israeli newspaper site to target politicians in Germany, Berlin’s cyber security watchdog said on Wednesday.

Cyber defenses installed after a 2015 hack of the parliament helped avert the attempted breaches, the Federal Office for Information Security (BSI) said in a statement.

The hackers appeared to use advertising running on the Jerusalem Post website to redirect users to a malicious site, it said.

The BSI looked into unusual activity on the parliament’s network early this year and has just completed a detailed analysis of the incident, which was first reported by the Sueddeutsche Zeitung newspaper on Wednesday.

At least 10 German lawmakers from all parliamentary groups were affected by the attempted hack, the Munich daily reported.

“The technical analysis is complete. The website of the Jerusalem Post was manipulated and had been linked to a malicious third party site,” the agency said in a statement.

“BSI found no malware or infections as part of its analysis of the Bundestag networks.”

The Jerusalem Post confirmed details of the attack with Reuters, but said no malware came from its own site and that it was fully protected against such attacks in the future.

“The Jerusalem Post website was attacked in January by foreign hackers,” the publisher said in a statement. “We immediately took action and together with Israeli cyber authorities successfully neutralized the threat.

Hackers can use infected banner advertisements to attack otherwise safe or secure sites. So-called “malvertising” appeared to be served up to the site via an unidentified third-party advertising network.

There was no suggestion from the German agency of any wrongdoing by the Jerusalem Post.

“SPEAR-PHISHING”

Security expert Graham Cluley said such “spear-phishing” attacks via malicious ads is highly unusual, but possible.

In this instance, the Jerusalem Post site could have served up German language ads to visitors with German internet addresses. However, he said it was unlikely this could be used to target specific politicians in Berlin.

This latest attack comes amid growing concern in Germany about cyber security and reports that Russia is working to destabilize the German government and could seek to interfere in the upcoming Sept. 24 national elections.

The Bundestag lost 16 gigabytes of data to Russian hackers in 2015, after which it revamped its software system with the help of the BSI and private contractors.

“The BSI believes that the defenses of the German Bundestag detected and prevented links to the website. The attack was therefore averted,” BSI President Arne Schoenbohm said in a statement.

A source familiar with the incident said it did not appear to be linked to APT28, a Russian hacking group also known as “Fancy Bear” that was blamed for the 2015 Bundestag hack and the 2016 hack of the U.S. Democratic National Committee.

(Reporting by Andrea Shalal in Berlin, Eric Auchard in London and Luke Baker in Jerusalem; Editing by Tom Heneghan)