Security readout for executives and security teams
Plain-English summary
CVE-2020-3403 lets a highly privileged local user on Cisco IOS XE place unsafe values that later run as root when the device reboots. The business risk is post-access persistence and full device compromise, not broad unauthenticated remote compromise.
Executive priority
Treat this as a targeted infrastructure risk. It is not described as internet-scale unauthenticated exploitation, but compromise of privileged network administration can give an attacker root-level persistence on affected devices.
Technical view
The Cisco IOS XE CLI insufficiently protects values passed to a startup script. An authenticated local attacker with privileged EXEC permissions can write values to a specific file, causing command execution with root privileges on subsequent reboots. The issue is CWE-78 command injection with CVSS 3.0 score 6.7.
Likely exposure
Exposure is limited to Cisco IOS XE devices where an attacker already has privileged EXEC access. The source bundle does not provide affected release ranges, fixed versions, or device model details.
Exploitation context
The bundle does not show CISA KEV status or cited evidence of active exploitation. Exploitation requires high privileges and local device access, but successful abuse can persist across restarts and execute with root authority.
Researcher notes
Key missing evidence is exact affected version coverage and Cisco's fixed-release mapping. Validation should stay source-grounded: confirm IOS XE presence, privileged access pathways, and whether Cisco advisory guidance applies to each device.
Mitigation direction
- Use Cisco's advisory to identify affected and fixed IOS XE releases.
- Upgrade or remediate according to Cisco vendor guidance.
- Restrict privileged EXEC access to trusted administrators only.
- Review local administrator accounts and remove unnecessary elevated access.
- Harden operational controls around device reboot and configuration changes.
Validation and detection
- Inventory Cisco IOS XE devices and record current software versions.
- Compare versions against Cisco's advisory and fixed-release guidance.
- Review privileged EXEC users, AAA policies, and recent access changes.
- Check logs and change records for privileged CLI activity before reboots.
- Confirm remediation through approved device configuration and version evidence.
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-78: Command execution behavior lookup
Command injection weaknesses can lead defenders to review execution techniques and command interpreter telemetry. 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-2020-3403 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
- Medium
- CVSS
- 6.7 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:L/AC:L/PR:H/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:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H0.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
6.7MediumVector: CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20200924 Cisco IOS XE Software Command Injection 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.