Microsoft Exchange Server Remote Code Execution Vulnerability (CVE-2021-42321)
Severity: high · Patch status: patched · Since 2021-11-17 · CVE-2021-42321
An authenticated attacker could leverage improper validation in cmdlet arguments within Microsoft Exchange and perform remote code execution. CISA added CVE-2021-42321 to its Known Exploited Vulnerabilities catalog on Nov 17, 2021, which means attackers are exploiting it in the wild. CISA reports known use in ransomware campaigns.
What to do
- Apply updates per vendor instructions.
- US federal agencies must remediate by Dec 1, 2021 (BOD 22-01); treat that as the outer limit.
Sources
All live incidents on Threat Watch
