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Microsoft: State-Sponsored Hackers Are Exploiting Log4j Vulnerability

The company also warns that cybercriminal groups are exploiting the flaw, likely to launch ransomware attacks.

 & Michael Kan Principal Reporter

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The critical Apache Log4j 2 vulnerability is paving the way for state-sponsored hackers to steal data and launch ransomware attacks, according to Microsoft. 

On Tuesday, the company warned it had observed nation-state hacking groups from China, Iran, North Korea, and Turkey trying to exploit the Log4j 2 flaw. Their activites include experimenting with the bug and abusing the flaw to drop malicious payloads and extract data from victims. 

According to Microsoft, an Iranian hacking group, dubbed Phosphorus or Charming Kitten, has allegedly been exploiting Log4j 2 to spread ransomware. A separate group from China called Hafnium has been observed leveraging the vulnerability to help it target potential victims. 

“In these attacks, Hafnium-associated systems were observed using a DNS service typically associated with testing activity to fingerprint systems,” Microsoft said. 

The vulnerability is raising alarm bells because Apache’s Log4j 2 software is used across the internet industry as a tool to log changes in a software or web application. By exploiting the flaw, a hacker can break into an IT system to steal data or run a malicious program. Not helping the problem is how the flaw is trivial to set up, making it all too easy for anyone to exploit it. 

The report from Microsoft underscores the need for the entire tech industry to patch the flaw before mayhem ensues. The company didn’t identify the state-sponsored hacking groups from North Korea or Turkey. But Microsoft added that other cybercriminal groups, called “access brokers,” have been spotted exploiting the Log4j 2 bug to gain a foothold into networks. 

“These access brokers then sell access to these networks to ransomware-as-a-service affiliates,” Microsoft said. “We have observed these groups attempting exploitation on both Linux and Windows systems, which may lead to an increase in human-operated ransomware impact on both of these operating system platforms.”

Other cybersecurity companies, including Mandiant, have also spotted state-sponsored hacking groups from China and Iran targeting the flaw. “We anticipate other state actors are doing so as well, or preparing to,” said Mandiant VP of Intelligence Analysis John Hultquist. “We believe these actors will work quickly to create footholds in desirable networks for follow-on activity, which may last for some time.”

About Our Expert

Michael Kan

Michael Kan

Principal Reporter

My Experience

I've been a journalist for over 15 years. I got my start as a schools and cities reporter in Kansas City and joined PCMag in 2017, where I cover satellite internet services, cybersecurity, PC hardware, and more. I'm currently based in San Francisco, but previously spent over five years in China, covering the country's technology sector.

Since 2020, I've covered the launch and explosive growth of SpaceX's Starlink satellite internet service, writing 600+ stories on availability and feature launches, but also the regulatory battles over the expansion of satellite constellations, fights with rival providers like AST SpaceMobile and Amazon, and the effort to expand into satellite-based mobile service. I've combed through FCC filings for the latest news and driven to remote corners of California to test Starlink's cellular service.

I also cover cyber threats, from ransomware gangs to the emergence of AI-based malware. In 2024 and 2025, the FTC forced Avast to pay consumers $16.5 million for secretly harvesting and selling their personal information to third-party clients, as revealed in my joint investigation with Motherboard.

I also cover the PC graphics card market. Pandemic-era shortages led me to camp out in front of a Best Buy to get an RTX 3000. I'm now following how the AI-driven memory shortage is impacting the entire consumer electronics market. I'm always eager to learn more, so please jump in the comments with feedback and send me tips.

The Best Tech I've Had:

  • My first video game console: a Nintendo Famicom
  • I loved my Sega Saturn despite PlayStation's popularity.
  • The iPod Video I received as a gift in college
  • Xbox 360 FTW
  • The Galaxy Nexus was the first smartphone I was proud to own.
  • The PC desktop I built in 2013, which still works to this day.

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