Security readout for executives and security teams
Plain-English summary
CVE-2020-3476 lets an authenticated local user on Cisco IOS XE overwrite files on the device host file system through a poorly validated CLI command. This is not described as remote unauthenticated compromise, but it can damage device integrity if privileged access is misused or stolen.
Executive priority
Treat as a moderate-priority network infrastructure integrity issue. It is less urgent than remotely exploitable router bugs, but important where many administrators, shared credentials, or weak device access controls exist.
Technical view
Cisco describes insufficient parameter validation in a specific IOS XE CLI command. With authenticated local access, an attacker could overwrite arbitrary files on the underlying host file system. CVSS 3.0 is 4.4: local attack vector, low complexity, high privileges required, high integrity impact, no confidentiality or availability impact scored.
Likely exposure
Exposure is limited to Cisco IOS XE environments. The source bundle does not identify affected release ranges or CPEs, so teams must map IOS XE devices against Cisco's advisory rather than assume all or no devices are affected.
Exploitation context
No KEV listing is provided and the supplied sources do not cite active exploitation. Abuse requires authenticated local access and high privileges, making compromised administrator accounts, unsafe shared credentials, or malicious insiders the more relevant threat paths.
Researcher notes
The bundle does not include the specific command, affected release table, fixed versions, or Cisco mitigation text. Avoid extrapolating beyond authenticated local arbitrary file overwrite on Cisco IOS XE until the vendor advisory is reviewed directly.
Mitigation direction
- Check Cisco's advisory for affected-release and remediation guidance.
- Restrict IOS XE CLI access to trusted administrative users only.
- Remove unused local accounts and unnecessary privileged access.
- Review AAA controls for accountability and least privilege.
- Monitor device logs for unusual privileged CLI activity.
Validation and detection
- Inventory Cisco IOS XE devices and running software releases.
- Compare discovered releases with Cisco advisory guidance.
- Review AAA logs for privileged local CLI sessions.
- Confirm administrative accounts are named, necessary, and current.
- Verify remediation status in change records or device inventory.
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
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ATT&CK lookup starting points
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CWE-552: Exact CWE lookup
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Open ATT&CK lookupFile access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2020-3476 mapping review
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Open ATT&CK lookup- Severity
- Medium
- CVSS
- 4.4 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N
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:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N0.83.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
4.4MediumVector: CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N
Source materials
- CVE List V5 sourceCVE List V5
- 20200924 Cisco IOS XE Software Arbitrary File Overwrite VulnerabilityCVE 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.
Files or Directories Accessible to External Parties
Files or Directories Accessible to External Parties represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.