Security readout for executives and security teams
Plain-English summary
This flaw could let a logged-in local user on Cisco IOS or IOS XE read files on the device flash filesystem that should be restricted. It is not described as remote code execution, but exposed files may contain sensitive operational data. Business urgency depends on who has CLI access and what sensitive files are stored on affected devices.
Executive priority
Treat this as a moderate-priority network infrastructure issue. Prioritize devices with shared administration, delegated CLI access, or sensitive files stored locally. It is less urgent than unauthenticated remote execution, but confidentiality impact can matter in regulated or segmented environments.
Technical view
CVE-2020-3477 is an information disclosure issue in the Cisco IOS and IOS XE CLI parser. Insufficient restriction handling during a specific command allows an authenticated local attacker to gain read-only access to otherwise inaccessible files on flash:. CVSS 3.0 is 5.5, with local attack vector, low complexity, low privileges, no user interaction, and high confidentiality impact.
Likely exposure
Exposure is most likely on Cisco IOS or IOS XE devices where non-admin or lower-privileged users can access the command line. The source bundle does not provide exact affected release ranges, so teams must use Cisco’s advisory to confirm exposure by platform and software version.
Exploitation context
The vulnerability requires authenticated local CLI access and low privileges. The provided sources do not support active exploitation, and the CVE is not marked KEV. The impact is confidentiality-only: read access to flash: files, with no integrity or availability impact stated.
Researcher notes
The source bundle identifies the CLI parser and insufficient restriction application but does not name the specific command or affected release matrix. Avoid assuming exploit availability or broad remote exposure. Validation should focus on authenticated CLI access paths, release applicability, and flash: file sensitivity.
Mitigation direction
- Check Cisco’s advisory for affected releases and fixed software guidance.
- Upgrade affected IOS or IOS XE software where Cisco provides a fixed release.
- Restrict CLI access to trusted administrators and necessary operational users.
- Review least-privilege roles for users with device command-line access.
- Reduce sensitive files stored on flash: where operationally feasible.
Validation and detection
- Inventory Cisco IOS and IOS XE devices and record exact software versions.
- Compare versions and platforms against the Cisco security advisory.
- Review local and remote CLI user privileges on potentially affected devices.
- Check whether flash: contains sensitive files that lower-privileged users should not read.
- Confirm remediation through vendor guidance and standard change validation.
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-20: 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 lookupCVE-2020-3477 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
- 5.5 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/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:L/UI:N/S:U/C:H/I:N/A:N1.83.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
5.5MediumVector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- 20200924 Cisco IOS and IOS XE Software Information Disclosure 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.
Improper Input Validation
Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.