Security readout for executives and security teams
Plain-English summary
This flaw can let an unauthenticated remote attacker disrupt Cisco IP Phones by overwhelming their TCP packet handling. Impact is availability: phones may stop receiving calls, drop active calls, or reload. For organizations dependent on these phones for operations, help desks, facilities, or emergency workflows, the business risk is service disruption rather than data theft.
Executive priority
Treat this as a high-priority availability risk for business voice services. Prioritize sites or departments where Cisco phones support customer operations, security desks, facilities, or emergency coordination. The urgency increases if phone networks are reachable beyond tightly controlled voice segments.
Technical view
CVE-2020-3574 affects Cisco IP Phones with Multiplatform Firmware. Cisco describes insufficient TCP ingress packet rate limiting, allowing high sustained crafted TCP traffic to cause call handling failures or device reloads. CVSS 3.1 is 7.5 high, with network attack vector, low complexity, no privileges, no user interaction, and high availability impact.
Likely exposure
Exposure is most relevant where affected Cisco IP Phones with Multiplatform Firmware are reachable from untrusted or broadly accessible networks. The supplied sources do not identify specific model versions, fixed firmware levels, or internet exposure data, so asset inventory and Cisco advisory review are required.
Exploitation context
The source bundle does not show CISA KEV listing or other evidence of active exploitation. The described attack is remote and unauthenticated but requires sustained crafted TCP traffic reaching the target phone. Do not assume exploitation in the environment without telemetry or incident evidence.
Researcher notes
The evidence supports availability-only impact and unauthenticated network reachability. The supplied data lacks model granularity, fixed-version details, exploit maturity, and workaround specifics. Validation should focus on asset matching, reachability, telemetry, and vendor advisory mapping, not proof-of-concept traffic generation.
Mitigation direction
- Review Cisco advisory for affected releases, fixed firmware, and supported workarounds.
- Inventory Cisco IP Phones running Multiplatform Firmware across voice networks.
- Apply Cisco-recommended updates or mitigations after operational validation.
- Restrict untrusted network paths to phone subnets where feasible.
- Monitor for unusual TCP traffic patterns targeting phone IP addresses.
Validation and detection
- Confirm deployed phone models and firmware against the Cisco advisory.
- Identify phone IP ranges reachable from user, guest, or external networks.
- Review network telemetry for sustained abnormal TCP traffic to phones.
- Check call availability and device reload history through normal operational monitoring.
- Document any compensating controls pending vendor-confirmed remediation.
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-371: 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-2020-3574 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
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20201104 Cisco IP Phone TCP Packet Flood Denial of Service 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.
State Issues
State Issues represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.