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HighCISA KEVExploited in the wildPublic exploit

Arbitrary Command Execution via Flawed SHA Authentication in Veritas Backup Exec Agent

IdentifiersCVE-2021-27878CWE-287

CVE-2021-27878 is a vulnerability in Veritas Backup Exec (versions 16.x, 20.x, and 21.1) where a flaw in the SHA authentication scheme allows an attacker to bypass authentication between a client and the Backup Exec Agent. Once authenticated, the attacker can execute arbitrary data management protocol commands, including those that allow execution of arbitrary system commands with system privileges. This vulnerability affects all agents on all platforms running the affected versions.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows a remote attacker to execute arbitrary commands on the target system with system privileges, potentially leading to full system compromise. This can be leveraged for lateral movement, privilege escalation, or as part of a ransomware attack. Exploits are known to exist in the wild as of March 2023.

Mitigation

If you can’t patch tonight, do this now.

If immediate upgrade is not possible, set the recommended registry key to disable the vulnerable SHA authentication scheme as per Veritas guidance. This will mitigate the risk until the system can be fully updated.

Remediation

Patch, then assume compromise.

Upgrade Veritas Backup Exec to version 21.2 or later, where the vulnerable SHA authentication scheme has been disabled and remediated. This is the only complete remediation.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Veritas TechnologiesBackup Execapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

1 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

1 SOURCESView more in app
What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware1

Malware families riding this exploit, with evidence and IOCs.

Detection signatures1

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES
MITRE CVE
cve.org · CVE-2021-27878
NVD
nvd.nist.gov/vuln/detail/CVE-2021-27878
MITRE CWE · CWE-287
cwe.mitre.org
Vendor Advisory
veritas.com/content/support/en_US/security/VTS21-001
Third Party Advisory
packetstormsecurity.com/files/168506/Veritas-Backup-Exec-Agent-Remote-Code-Execution.html
US Government Resource
cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27878
Arbitrary Command Execution via Flawed SHA Authentication in Veritas Backup Exec Agent (CVE-2021-27878) | Mallory