Cyber criminals have launched a new campaign that targets Sangoma PBX, an open source web GUI that manages communications toolkit Asterisk, security researchers have said.

The attack exploits CVE-2019-19006, a critical vulnerability in Sangoma private branch exchange (PBX), which grants the attacker admin access to the system and gives them control over its functions.

Nearly 1,200 organisations worldwide over past 12 months are said to have been targeted, with the main purpose of the campaign being to lift phone numbers and gain live access to compromised VoIP services, according to a blog by researchers at Check Point Software.

Countries targeted include the Netherlands, Belgium, US, Columbia, and Germany. However, over half of the attacks so far have been aimed at companies based in the UK, in industries such as government, military, insurance, finance, and manufacturing.

“While investigating the exploitations, researchers identified several online profiles associated with private Facebook groups that deal with VoIP, and more specifically, SIP server exploitation,” said researchers Ido Solomon, Ori Hamama and Omer Ventura, in a joint blog post. 

They added that investigations into the source of the attacks suggested that most hackers were based in Gaza, the West Bank, and Egypt.

It was also concluded that the group has mostly tried to gain access to phone numbers, and sell these on to other groups, and grant access to compromised VoIP services “to the highest bidders, who can then exploit those services for their own purposes”.

Researchers said that hackers could also use the compromised systems to support further attacks, such as using the system resources for cryptocurrency mining, spreading laterally across the company network, or launching attacks on outside targets, while masquerading as representatives from the compromised company.

Companies using vulnerable systems have been urged to change all default passwords and analyse call billings on a regular basis as well as applying patches to close the CVE-2019-19006 vulnerability that hackers are exploiting.