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CVE Record

CVE-2021-1386: Cisco Advanced Malware Protection for Endpoints Windows Connector, ClamAV for Windows, and Immunet DLL Hijacking Vulnerability

A vulnerability in the dynamic link library (DLL) loading mechanism in Cisco Advanced Malware Protection (AMP) for Endpoints Windows Connector, ClamAV for Windows, and Immunet could allow an authenticated, local attacker to perform a DLL hijacking attack on an affected Windows system. To exploit this vulnerability, the attacker would need valid credentials on the system. The vulnerability is due to insufficient validation of directory search paths at run time. An attacker could exploit this vulnerability by placing a malicious DLL file on an affected system. A successful exploit could allow the attacker to execute arbitrary code with SYSTEM privileges.

HighCVSS 7Not KEV-listedUpdated
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This is a Windows local privilege escalation issue in Cisco security products. A logged-in attacker could abuse unsafe DLL loading to run code with SYSTEM privileges. It matters because endpoint security software runs with high trust, but exploitation requires existing local access and valid credentials.

Executive priority

Prioritize remediation on shared workstations, servers, and high-value endpoints where local compromise could become full SYSTEM control. This is not described as remotely exploitable, but it can materially worsen an existing foothold.

Technical view

CVE-2021-1386 is a CWE-427 DLL search path validation flaw affecting Cisco AMP for Endpoints Windows Connector, ClamAV for Windows, and Immunet. The CVSS 3.1 score is 7.0. The attack is local, high complexity, requires low privileges, no user interaction, and can yield SYSTEM-level code execution.

Likely exposure

Exposure is limited to Windows systems running the named Cisco endpoint products. The source bundle does not provide affected version ranges, so teams must compare deployed versions against Cisco’s advisory.

Exploitation context

The bundle states exploitation requires valid local credentials and placing a malicious DLL on the affected system. KEV is false, and the provided sources do not state active exploitation in the wild.

Researcher notes

The key behavior is insecure runtime directory search path validation. Validate exposure through product presence, version status, and writable path review. Avoid assuming exploit availability or affected versions beyond the sources.

Mitigation direction

  • Review Cisco’s advisory for affected and fixed versions.
  • Apply vendor-recommended updates or workarounds where applicable.
  • Restrict local interactive access to affected Windows endpoints.
  • Limit write permissions in product and service-related directories.
  • Monitor for suspicious DLL creation near endpoint security components.

Validation and detection

  • Inventory Windows endpoints running the named Cisco products.
  • Compare installed versions with Cisco’s advisory.
  • Check whether local users can write to sensitive product paths.
  • Review EDR logs for unexpected DLL loads by security processes.
  • Confirm endpoint security services are running supported versions.
Prepared
Confidence
high
Sources
3

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-427: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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cve · low confidence lookup

CVE-2021-1386 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
7 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7CVSS 3.1HighCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H15.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7High
CVSS 3.1 vector shape for CVE-2021-1386Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone
Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
CiscoCisco AMP for Endpointsn/aListed
Weakness

CWE details

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-427 · source CWE mapping

Uncontrolled Search Path Element

Uncontrolled Search Path Element represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.