Security readout for executives and security teams
Plain-English summary
This Cisco Snort engine flaw can let someone on the same adjacent network crash operational availability by forcing affected devices to fill disk space. The result can be serious: administrators may be unable to log in, and devices may fail to boot correctly. Cisco says recovery may require manual intervention through TAC.
Executive priority
Treat this as a high-priority availability risk for network security infrastructure. Prioritize exposed, business-critical Cisco devices because downtime can block administration and may require vendor-assisted recovery.
Technical view
CVE-2021-1285 is improper error-condition handling in the Snort Ethernet Frame Decoder. An unauthenticated adjacent attacker can send malicious Ethernet frames through an affected device, causing disk exhaustion and denial of service. Cisco released software updates and states there are no workarounds.
Likely exposure
Exposure is most likely where Cisco products use Cisco UTD SNORT IPS Engine Software in the listed affected versions and inspect adjacent Ethernet traffic. The provided source does not enumerate every affected Cisco product beyond this software component.
Exploitation context
The bundle does not show CISA KEV listing or active exploitation evidence. Attack access is adjacent, unauthenticated, low complexity, and availability-focused. Successful exploitation may require TAC-assisted recovery rather than simple service restart.
Researcher notes
Scope validation should focus on the Snort Ethernet Frame Decoder in Cisco UTD SNORT IPS Engine Software. The CVSS vector is adjacent network, no privileges, no user interaction, changed scope, and high availability impact. No confidentiality or integrity impact is described.
Mitigation direction
- Review the Cisco advisory for affected software trains and fixed releases.
- Upgrade affected Cisco UTD SNORT IPS Engine Software to Cisco-provided fixed versions.
- Do not rely on a workaround; Cisco states none addresses this vulnerability.
- Plan maintenance because failed devices may need manual recovery.
- Contact Cisco TAC if a device cannot boot or admins cannot log in.
Validation and detection
- Inventory Cisco devices using UTD SNORT IPS Engine Software.
- Compare installed versions against the affected version list and Cisco advisory.
- Confirm whether affected devices process traffic from adjacent untrusted networks.
- Check for disk exhaustion, login failures, or boot failures on suspected devices.
- Verify remediation by confirming software is updated to a Cisco fixed release.
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
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CWE-770: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-1285 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
- 7.4 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X
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:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X2.84Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
7.4HighVector: CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X
Source materials
- CVE List V5 sourceCVE List V5
- cisco-sa-snort-ethernet-dos-HGXgJH8nCVE reference
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.
Allocation of Resources Without Limits or Throttling
Allocation of Resources Without Limits or Throttling represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.