North Korean cybercriminals have stepped up attacks targeting software supply chains in a bid to steal confidential information and core technologies from government agencies and tech companies, according to Seoul’s spy agency.

The National Intelligence Service (NIS) said in a press release on Tuesday that it recently detected DPRK threat actors employing “sophisticated techniques” to carry out supply chain attacks, in which cybercriminals compromise third-party suppliers or vendors to gain access to the actual targets’ systems.

The agency observed the North Koreans employing three main types of software supply chain attacks: attacking IT service providers to infiltrate targets’ systems indirectly,