Another threat actor is actively exploiting the so-called PrintNightmare vulnerability (CVE-2021-1675 / CVE-2021-34527) in Windows’ print spooler service to spread laterally across a victim’s network as part of a recent ransomware attack, according to Cisco Talos Incident Response research. While previous research found that other threat actors had been exploiting this vulnerability, this appears to be new for the threat actor Vice Society.
Talos Incident Response’s research demonstrates that multiple, distinct threat actors view this vulnerability as attractive to use during their attacks and may indicate that this vulnerability will continue to see more widespread adoption and incorporation by various adversaries moving forward. For defenders, it is important to understand the attack lifecycle leading up to the deployment of ransomware. If users have not already, they should download the latest patch for PrintNightmare from Microsoft.