CVE-2021-27876
Veritas Backup Exec Agent File Access Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 28 April 2023). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
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. By using crafted input parameters in one of these commands, an attacker can access an arbitrary file on the system using System privileges.
- CVSS 3.1
- 8.1 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 13.52% probability · 96th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Listed 7 April 2023 · due 28 April 2023 · used in ransomware campaigns
- Affected
- veritas/backup exec
- Source
- cve@mitre.org
EPSS 13.5% since 26 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
CISA notes
Apply updates per vendor instructions. https://www.veritas.com/support/en_US/security/VTS21-001; https://nvd.nist.gov/vuln/detail/CVE-2021-27876
References
- http://packetstormsecurity.com/files/168506/Veritas-Backup-Exec-Agent-Remote-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
- https://www.veritas.com/content/support/en_US/security/VTS21-001#issue2Vendor Advisory
- http://packetstormsecurity.com/files/168506/Veritas-Backup-Exec-Agent-Remote-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
- https://www.veritas.com/content/support/en_US/security/VTS21-001#issue2Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27876US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.