Security readout for executives and security teams
Plain-English summary
Cisco AnyConnect for Windows had flaws in install, uninstall, and upgrade handling that could let a signed-in local attacker run malicious code with SYSTEM privileges. This is not described as remotely exploitable, but compromise of one low-privilege Windows account could become full control of that endpoint.
Executive priority
Treat this as a high-priority endpoint hardening issue, not an internet-facing emergency. The business risk is privilege escalation after local account compromise, especially on laptops and administrator workstations using AnyConnect.
Technical view
CVE-2021-1429 covers multiple DLL and executable hijacking issues in Cisco AnyConnect Secure Mobility Client for Windows lifecycle processes. The CVSS 3.1 score is 7.0, with local attack vector, high complexity, low privileges required, no user interaction, and high confidentiality, integrity, and availability impact.
Likely exposure
Windows endpoints running Cisco AnyConnect Secure Mobility Client are the relevant exposure. The supplied bundle does not identify exact affected versions, so vulnerability managers should compare installed AnyConnect versions against Cisco’s advisory and internal software inventory.
Exploitation context
The source bundle does not show CISA KEV listing or cited active exploitation. Exploitation requires valid local Windows credentials and high-complexity conditions, but successful exploitation can execute arbitrary code as SYSTEM.
Researcher notes
CWE-378 is cited, and the described impact is local privilege escalation through DLL or executable hijacking during AnyConnect lifecycle operations. Evidence is incomplete for exact vulnerable versions and fixes in the provided bundle; rely on Cisco’s advisory for authoritative release details.
Mitigation direction
- Check Cisco’s advisory for fixed releases and upgrade guidance.
- Prioritize Windows endpoints with Cisco AnyConnect installed.
- Restrict local logon access to trusted users only.
- Monitor software install, uninstall, and upgrade workflows on affected endpoints.
- Use endpoint controls to detect unexpected SYSTEM-level process launches.
Validation and detection
- Inventory Cisco AnyConnect Secure Mobility Client installations on Windows.
- Compare installed versions with Cisco’s advisory.
- Confirm whether install, uninstall, or upgrade workflows are present in endpoint logs.
- Review endpoint alerts for suspicious DLL or executable loading around AnyConnect operations.
- Document remediation status for each affected Windows asset.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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-378: 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.
Open ATT&CK lookupExecution 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.
Open ATT&CK lookupCVE-2021-1429 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- 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
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.
CVSS vector scores
1 official scoreWe 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.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H15.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7HighVector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20210505 Cisco AnyConnect Secure Mobility Client for Windows DLL and Executable Hijacking VulnerabilitiesCVE reference · vendor-advisory, x_refsource_CISCO
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Creation of Temporary File With Insecure Permissions
Creation of Temporary File With Insecure Permissions represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.