Security readout for executives and security teams
Plain-English summary
CVE-2021-1428 is a Cisco AnyConnect for Windows privilege escalation issue. A logged-in local attacker could abuse how the client handles DLL or executable files during install, uninstall, or upgrade activity to run code as SYSTEM. This is serious on managed Windows endpoints, but the provided sources do not show remote exploitation or confirmed active exploitation.
Executive priority
Treat this as a high-priority endpoint remediation item where AnyConnect for Windows is deployed. It is not described as remotely exploitable, but SYSTEM-level code execution can turn ordinary local access into full endpoint compromise.
Technical view
Multiple flaws in Cisco AnyConnect Secure Mobility Client for Windows install, uninstall, and upgrade processes allow authenticated local DLL or executable hijacking. Successful exploitation could execute arbitrary code with SYSTEM privileges. The CVSS 3.1 score is 7.0, with local attack vector, high complexity, low privileges required, and no user interaction.
Likely exposure
Exposure is limited to Windows systems running Cisco AnyConnect Secure Mobility Client. The provided bundle does not identify specific affected or fixed versions, so teams must map installed client versions against Cisco's advisory.
Exploitation context
The source bundle does not indicate CISA KEV listing or active exploitation. Exploitation requires valid Windows credentials on the target system and is local, not network-direct. Impact is high because SYSTEM execution can compromise the endpoint.
Researcher notes
Key constraints are local access, valid credentials, high attack complexity, and no user interaction. The weakness is categorized as CWE-378. The provided evidence lacks affected-version and fixed-release details, so Cisco's advisory should be treated as the authoritative source for applicability.
Mitigation direction
- Review Cisco's advisory for affected and fixed AnyConnect for Windows versions.
- Inventory Windows endpoints with Cisco AnyConnect Secure Mobility Client installed.
- Upgrade or remediate matched installations according to Cisco guidance.
- Prioritize devices used by privileged users or administrators.
- Monitor vendor guidance if version details are incomplete internally.
Validation and detection
- Confirm whether Cisco AnyConnect Secure Mobility Client is installed on Windows endpoints.
- Record installed client versions and compare them with Cisco's advisory.
- Check endpoint management logs for recent install, uninstall, or upgrade activity.
- Verify remediation by confirming the post-update AnyConnect version.
- Document any systems where vendor applicability cannot be confirmed.
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-2021-1428 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.