Hackers used the Log4j flaw to gain access before moving across a company’s network, say security researchers

North Korean hacking group Stonefly, also known as DarkSeoul, exploited a cybersecurity vulnerability in Log4j to breach the network of an undisclosed engineering firm connected to military and energy sectors. Researchers found that the attackers compromised at least 18 computers, using custom-made malware and exploiting an unpatched security flaw, despite warnings to upgrade security measures. Researchers suggest Stonefly has links with notorious North Korean hacking group Lazarus, and focuses on selective attacks to gain strategic intelligence.