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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 28 Apr 2023. Known ransomware use
Backup ExecApplication · Veritas

CVE-2021-27878

HIGH · 8.8 CVSS v3.1 Published 2021-03-01
Fix available
A fix is available. Upgrade to 21.2 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild Ransomware Public exploit Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Veritas Backup Exec before version 21.2 contains a flaw in the SHA Authentication scheme used for client-to-Agent communication. An attacker can bypass authentication and gain unauthorized access, then execute data management protocol commands that allow arbitrary command execution with SYSTEM privileges.

MitigationUpgrade Veritas Backup Exec to version 21.2 or later to remediate this vulnerability.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Backup ExecApplication
Affected:< 21.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Backup Exec version
    Open Backup Exec console, go to Help > About, or check the installed programs list in Windows Control Panel. Note the exact version number displayed.
    Affected if Version is earlier than 21.2 (e.g., 21.0, 20.x, older releases)
  2. Confirm Backup Exec Agent is installed
    Check Windows Services for 'Backup Exec Agent' service, or look for Agent installation in Program Files/Veritas/Backup Exec/Agents.
    Affected if Agent component is installed on the system
  3. Verify Agent network listening status
    Run command 'netstat -an | findstr LISTENING' and look for ports associated with Backup Exec Agent (typically 10000, 6103, or configurable agent ports). Check if these ports are bound to external interfaces.
    Affected if Agent ports are listening on external/network interfaces (not localhost only)
  4. Check SHA Authentication configuration
    In Backup Exec console, navigate to Agent properties or authentication settings. Look for SHA-based authentication method configuration for agent communication.
    Affected if SHA Authentication scheme is enabled for agent communications
  5. Review network access controls
    Examine firewall rules or network segmentation affecting Backup Exec Agent ports. Check if unrestricted access is allowed from untrusted network segments.
    Affected if Agent is accessible from network addresses outside trusted management infrastructure

System is affected if Backup Exec version is below 21.2 AND the Agent component is network-accessible with SHA Authentication enabled.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 21.2 or later
Fixed in 21.2
Interim mitigation

Upgrade Veritas Backup Exec to version 21.2 or later to remediate this vulnerability.

Recommended fix High confidence

Backup Exec 21.2 or later

  1. 1. Review Veritas Backup Exec 21.2 release notes and upgrade documentation for pre-upgrade requirements
  2. 2. Create a full backup of the Backup Exec configuration and database
  3. 3. Download Backup Exec 21.2 or later from Veritas Support website (www.veritas.com/support)
  4. 4. Apply the upgrade following Veritas installation documentation
  5. 5. Verify the upgrade was successful by checking the version in Backup Exec administration console
  6. 6. Test critical backup and restore operations to ensure functionality
Caveat Review Veritas compatibility lists for agent versions and backup storage devices before upgrading; some legacy agent versions may require updates

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Backup Exec Exploited in the wild — priority engagement
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,328.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-27878 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data