From Vienna’s rooftops, the Kremlin is listening in

From the upper floors of Vienna’s former imperial riding school, a cluster of satellite dishes can be made out behind the golden domes of the Russian Orthodox cathedral.

All embassies need to communicate securely with their capitals. But these dishes, sat atop Russia’s representation in central Vienna, are there for something different, according to experts and western security officials.

For one thing, they do not point east.

Four years into the war in Ukraine, the roofs of Russia’s sprawling diplomatic premises in the Austrian capital have quietly revived one of their most important cold war functions: as the Kremlin’s largest covert signals intelligence platform in the west.

“It’s one of our main concerns about Russian activity here. We know they have been targeting Nato government and military communications with what they’ve got,” said one senior European diplomat based in Vienna. “Vienna has really taken on a lot of importance for them . . . it’s their hub in Europe.”

From Vienna, Russia is not just snooping on satellite and electronic communications in Europe but also on those in the Middle East and Africa, said the officials and experts.

While the 2022 invasion of Ukraine prompted a wave of Russian diplomatic expulsions from most European countries, neutral Austria took a more permissive approach in regard to Moscow’s outposts.

Even Austria’s own domestic intelligence agency (DSN) recently warned that “the technical capabilities and adaptable alignment of the Russian Federation’s SIGINT stations [in Vienna] pose a significant security risk in counter-espionage”.

A western intelligence official in Vienna said they had monitored the installation of several new dishes and other unusual installations on rooftops in the past two years. Also of interest was the frequency with which some of the Russian dishes are being repositioned, the official said.

That indicates that they are being very actively used to target multiple satellites, the official added, pointing out that dishes used for embassy communications back to Moscow would not need to be moved.

On the eve of the Munich Security Conference last month, for example, one of the largest rooftop dishes was reoriented. It returned to its previous position the day after the conference ended. The MSC is Europe’s most important annual global gathering of security and defence officials and politicians.

Tracking such dish repositioning can offer a rare insight into Russian SIGINT interests.

While western intelligence agencies are reluctant to talk about Russia’s technical capabilities, open-source analysis can fill in the blanks.

Hundreds of high-resolution pictures of rooftop equipment seen by the FT and analysed by experts provide some clues as to what Russia’s spies are interested in.

The pictures were taken over the past two years by NomenNescio (Latin for “I do not know the name”) — a group of Vienna-based electronic engineers and communication enthusiasts documenting the roof of the largest Russian compound in Vienna, jokingly dubbed “Russencity”.

Situated on the east bank of the Danube, Russencity is a nine-acre facility surrounded by high-security fences and comprising several residential buildings and a school for the children of Russian diplomats.

At its centre is a six-storey octagonal building housing the Russian mission to the UN, with a roof covered in satellite dishes.

Erich Moechel, a spokesperson for NomenNescio, said that the group took high-resolution images of that rooftop and aerial photographs to work out which satellites the Russians were interested in at any given time.

Most of the Russencity dishes point west, said Moechel, towards some of the 18 geostationary satellites located between the prime meridian and the 15th longitude. Pictures of the satellite receivers (known as low-noise converters, or LNCs) mounted in front of the dishes reveal the frequencies they home in on.

“We identified four satellites,” said Moechel: Eutelsat 3B and 10B and SES5 and Rascom QAF1. The quartet all serve to provide communications between Africa and Europe.

NomenNescio pictures also show that Russian experts have installed special lenses in front of their LNCs, which allow them to “squint” at satellite signals in a much broader range than a usual set-up would allow, Moechel said.

Vienna is “optimally positioned” for this, said Moechel, pointing out that just over 100km south-east, in Aflenz, is one of Europe’s main satellite communication stations. The Austrian capital is also of interest as a base for many international organisations such as UN agencies, the OSCE, IAEA and OPEC — all of which have their own satellite terminals.

Russencity, which broke ground in 1983, was most likely designed for signals intelligence work from the outset, said Thomas Riegler, an Austrian historian specialising in espionage. “That intention was probably built into it.”

The compound was ordered by Yuri Andropov, the longtime head of the KGB who briefly led the Soviet Union. It was designed by the city architect of Moscow as “a statement of the strategic importance of Vienna”, Riegler said.

The investment paid off. At a time when Russian operatives are under huge pressure elsewhere in Europe, Vienna is a boomtown for them.

Russia still has around 500 diplomatic staff in the city, with as many as a third of them thought to be covertly working as spies, according to Austrian intelligence assessments.

Russencity is one of just several sites engaged in SIGINT activities. “So far we have only really analysed a very small part of the activity,” said Moechel.

Photographs of the Russian embassy behind the cathedral, for example, show dishes and other equipment detected at Russencity.

The Russian cultural centre in Brahmsplatz also has significant rooftop installations. And there are at least four dishes on the roof of a former sanatorium at Sternwartestrasse — once a clinic used secretly by Stalin’s NKVD bosses for recuperation and acquired by the Russians in 1953.

At another site close to the Danube, there are signs of recent activity. Not many people know that the low pair of apartment buildings also belong to the Russian state. For many years the buildings lay dormant. Now there are security cameras. The entrance has been reinforced. A bus turns up daily outside. And satellite images show a small hut has been installed on the roof.

Similar huts can be spotted on the roofs of the US and British embassies. Moechel said they are built to cover sensitive equipment with low-density material.

Major intelligence powers all collect SIGINT in Vienna, Riegler said. “The Russians just do it very openly, and often in quite a crude way.” That comes from a position of confidence, he added.

Austria’s counter-intelligence can do little: under Austrian law, espionage cannot be prosecuted unless it is carried out against national interest. Despite the DSN’s recommendations, Vienna has shown little interest in expelling diplomats or taking other measures against Russian operatives.

The DSN provided the government with a list of people it knows operate Russia’s secret signals intelligence stations in Vienna. But officials believe acting on such information will only provoke Russia.

The Austrian interior ministry declined to comment beyond the findings of the most recent DSN report.

The Russian embassy in Vienna did not respond to a request for comment.

Austria is neutral, and not a Nato member, but it has been working hard to repair its security relationship with other European countries in recent years. Part of that has been recognising — behind closed doors at least — that Russia is a common threat.

Diplomatic expulsions may not be on the table, but, said one Austrian security official, that does not mean that there are not other ways in which Austria can help deter and disrupt Russian activity hostile to European interests. A lot of information about what goes on in Vienna gets shared, the official said.

In intelligence, they added, it was sometimes better to watch than to act.