Security readout for executives and security teams
Plain-English summary
This flaw can let malicious HTTP file traffic slip past Snort-based file policy controls on affected Cisco products. It does not give an attacker direct system control, but it can weaken a security gateway’s ability to block malicious payload delivery.
Executive priority
Treat as a moderate-priority control bypass. Prioritize faster remediation where HTTP file policy is a key malware prevention control, especially on high-traffic ingress or egress inspection paths.
Technical view
CVE-2021-1223 is caused by incorrect handling of an HTTP Range header in the Snort HTTP detection engine. An unauthenticated remote attacker can send crafted HTTP packets through an affected device and bypass configured HTTP file policy enforcement. The CVSS score is 5.8.
Likely exposure
Exposure is most likely where Cisco Firepower Threat Defense Software or Snort-based inspection is deployed with HTTP file policies enabled. The bundle does not provide a complete affected-version list.
Exploitation context
The source bundle does not show CISA KEV listing, active exploitation, or public exploit confirmation. Exploitation requires crafted HTTP traffic to pass through an affected inspection point with relevant HTTP file policy controls.
Researcher notes
This is a detection and policy-enforcement bypass, not an RCE in the provided evidence. The bundle names Cisco Firepower Threat Defense Software and Debian Snort updates but does not provide full Cisco affected-version details.
Mitigation direction
- Review Cisco advisory applicability for deployed products and versions.
- Apply Cisco vendor fixes or guidance where affected.
- Apply Debian Snort security updates where Debian packages are used.
- Inventory devices enforcing HTTP file policy with Snort inspection.
- Monitor vendor advisories for fixed-release and workaround details.
Validation and detection
- Confirm whether Cisco Firepower Threat Defense Software is deployed.
- Check whether HTTP file policies are enabled on affected inspection paths.
- Compare running versions against Cisco and Debian advisories.
- Verify Snort or product updates are installed where applicable.
- Review logs for suspicious HTTP file transfers allowed unexpectedly.
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-693: 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-2021-1223 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
- 5.8 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/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:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N3.91.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
5.8MediumVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- 20210113 Multiple Cisco Products Snort HTTP Detection Engine File Policy Bypass VulnerabilityCVE reference · vendor-advisory
- [debian-lts-announce] 20230210 [SECURITY] [DLA 3317-1] snort security updateCVE reference · mailing-list
- DSA-5354CVE reference · vendor-advisory
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.
Protection Mechanism Failure
Protection Mechanism Failure represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.