CVE-2021-27878

CVE-2021-27878 is actively exploited and listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added April 7, 2023, with confirmed use in ransomware campaigns.

An issue was discovered in Veritas Backup Exec before 21.2. The communication between a client and an Agent requires successful authentication, which is typically completed over a secure TLS communication. However, due to a vulnerability in the SHA Authentication scheme, an attacker is able to gain unauthorized access and complete the authentication process. Subsequently, the client can execute data management protocol commands on the authenticated connection. The attacker could use one of these commands to execute an arbitrary command on the system using system privileges.