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Vulnerabilities/CVE-2021-27878Public Intelligence Dossier
Source: veritas · Limited verification•Last verified: •Collection Degraded
CVE-2021-27878ListedHIGH (raw)CVSS 9.0NVD-CWE-noinfo

An issue was discovered in Veritas Backup Exec before 21.2

Published: 02 Mar 2021•Last updated: 17 Jun 2026, 09:15 AM IST•Source identifier: cve@mitre.org
Dossier completeness: source-provided sections 3 / 3 · rule guidance available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Listed
Added07 Apr 2023
Due28 Apr 2023
RansomwareKnown
CVSS score
9.0HIGH (raw)
AV:N/AC:L/Au:S/C:C/I:C/A:C
Metric sourcenvd@nist.gov
EPSS probability
24%0.240
Percentile98th
Weakness type
NVD-CWE-noinfo
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

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.

SOC priority

Immediate Attention

Actively exploited (source statement)

Yes

Publicly disclosed

Unknown

Risk basis: CISA KEV exploitation signal; HIGH severity; Source-confirmed exploitation or CISA KEV/ransomware metadata

Affected Products & Remediation

1 source-backed product
Affected products and versions (source)
  • veritas backup exec · < 21.2 · NVD CPE · Source
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

  • CISA KEV: Apply updates per vendor instructions.

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Listed
Exploited (source statement)
Yes
Publicly disclosed (source)
Unknown

CISA required action: Apply updates per vendor instructions.

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

Matched kev-network-exposure (CVSS AV:N, CISA KEV Listed)

Exposure

  1. Identify assets with the exact CVE and confirm the affected product/version against the advisory.Telemetry: DeviceTvmSoftwareVulnerabilities · KEV listing raises urgency, but inventory is needed to establish local exposure. · Rule kev-network-exposure

Exploitation evidence

  1. Review relevant edge or application access logs for unusual requests around the advisory window.Telemetry: CommonSecurityLog · Log review is a hunting hypothesis; KEV listing alone does not show local exploitation. · Rule kev-network-exposure

Response

  1. Recheck the affected assets after the source-stated mitigation or update is applied.Telemetry: DeviceTvmSoftwareVulnerabilities · A follow-up inventory check verifies local remediation. · Rule kev-network-exposure

CISA KEV Record

Catalog entry
07 Apr 2023
Required action due
28 Apr 2023
Known ransomware use
Known

Apply updates per vendor instructions.

Change History & Source Data

— No recorded material change

CNA / source
cve@mitre.org
Record status · verification
UPDATED · CISA KEV confirmed
CPE
cpe:2.3:a:veritas:backup_exec:*:*:*:*:*:*:*:*

Linked by the query's stored exact CVE association. Review required tables and validation status before use.

Detection Hunting Query
Target: DeviceTvmSoftwareVulnerabilities•Defender XDR
Detect endpoints exposed to CVE-2021-27878
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2021-27878
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2021-27878"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc
Schema Checked · Not runtime validatedSource: SecOps Signal deterministic template · Limited verificationStatic screening: Passed structure and schema checks; tenant execution is not verified.

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Correlated briefings

SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.