Security readout for executives and security teams
Plain-English summary
This issue can let an unauthenticated remote attacker force affected Cisco ASA or FTD devices to reload, causing a denial of service. The business impact is interruption of firewall or VPN availability, not data theft or system takeover based on the provided sources.
Executive priority
Treat this as a high-priority availability risk for perimeter firewall and VPN infrastructure. It does not indicate data compromise in the provided sources, but a reload of an affected device can disrupt remote access and network security operations.
Technical view
CVE-2019-15256 affects the IKEv1 feature in Cisco ASA Software and Cisco FTD Software. Improper system memory management can allow malicious IKEv1 traffic to exhaust memory resources and trigger device reload. CVSS 3.0 is 8.6, with network attack vector, low complexity, no privileges, and high availability impact.
Likely exposure
Exposure is most likely where Cisco ASA or FTD devices have IKEv1 reachable from untrusted networks. The source bundle does not provide exact affected versions, CPEs, or fixed-release details, so asset owners must verify applicability against Cisco's advisory.
Exploitation context
The source bundle does not support claiming active exploitation; CISA KEV status is false. The vulnerability is remotely reachable and does not require valid VPN credentials. Cisco's description says the attacker's source address does not need to match a crypto map peer statement.
Researcher notes
The provided evidence identifies the vulnerable feature, attack preconditions, and impact, but not exact affected versions, fixed versions, or field exploitation. Avoid broad product assumptions beyond Cisco ASA Software and Cisco FTD Software until the Cisco advisory is checked.
Mitigation direction
- Review Cisco's advisory for affected versions and fixed releases.
- Apply Cisco-published software updates or mitigations after confirming applicability.
- Prioritize externally reachable ASA and FTD devices with IKEv1 enabled.
- Reduce unnecessary IKEv1 exposure using vendor-approved configuration guidance.
- Monitor affected devices for unexpected reloads and memory exhaustion symptoms.
Validation and detection
- Inventory Cisco ASA and FTD devices that expose IKEv1.
- Check software versions against Cisco's advisory.
- Confirm whether IKEv1 is enabled on externally reachable interfaces.
- Review logs and uptime for unexplained reloads around IKEv1 activity.
- Document remediation status for each exposed device.
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-399: Exact CWE lookup
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Open ATT&CK lookupCVE-2019-15256 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 8.6 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/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:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H3.94Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
8.6HighVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20191002 Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software IKEv1 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.
Resource Management Errors
Resource Management Errors represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.