Security readout for executives and security teams
Plain-English summary
This flaw can let an unauthenticated internet attacker overload Cisco ASA or Firepower Threat Defense devices that expose WebVPN login. The business impact is availability: VPN access or firewall services may degrade or become unavailable during an attack.
Executive priority
Treat as high priority for internet-facing VPN infrastructure because exploitation can disrupt remote access and perimeter services without authentication. Prioritize validation and vendor-guided remediation for exposed devices.
Technical view
CVE-2018-15388 is a CWE-400 resource consumption issue in the WebVPN login process. Multiple WebVPN login requests can create excessive processing load, increasing CPU utilization and causing denial of service. CVSS v3.0 is 8.6 with network, low-complexity, unauthenticated attack conditions.
Likely exposure
Exposure is most likely where Cisco ASA Software or Cisco FTD Software has WebVPN reachable from untrusted networks. The provided bundle does not identify exact affected versions, so inventory and Cisco advisory comparison are required.
Exploitation context
The sources describe unauthenticated remote exploitation for denial of service. The bundle does not cite CISA KEV listing or public active exploitation evidence, so active exploitation should not be assumed from these sources alone.
Researcher notes
The public bundle supports the root cause, attack conditions, impact, CVSS, and affected product families. It does not provide specific affected versions, fixed versions, or confirmed exploitation, so those details must be taken from Cisco’s advisory or vendor support.
Mitigation direction
- Review the Cisco advisory for affected and fixed release information.
- Upgrade affected Cisco ASA or FTD software according to Cisco guidance.
- Restrict WebVPN exposure to trusted networks where operationally possible.
- Monitor device CPU and VPN availability for abnormal spikes.
Validation and detection
- Inventory Cisco ASA and FTD devices with WebVPN enabled.
- Confirm whether WebVPN login is reachable from the internet or untrusted networks.
- Compare deployed versions against Cisco advisory guidance.
- Review device telemetry for sustained CPU spikes during WebVPN login activity.
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-400: 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-2018-15388 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
- 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
- 20190501 Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software WebVPN 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.
Uncontrolled Resource Consumption
Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.