Secure Firewall Threat DefenseApplication · Cisco
CVE-2020-3187
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct directory traversal attacks and obtain read and delete access to sensitive files on a targeted system. The vulnerability is due to a lack of proper input validation of the HTTP URL. An attacker could exploit this vulnerability by sending a crafted HTTP request containing directory traversal character sequences. An exploit could allow the attacker to view or delete arbitrary files on the targeted system. When the device is reloaded after exploitation of this vulnerability, any files that were deleted are restored. The attacker can only view and delete files within the web services file system. This file system is enabled when the affected device is configured with either WebVPN or AnyConnect features. This vulnerability can not be used to obtain access to ASA or FTD system files or underlying operating system (OS) files. Reloading the affected device will restore all files within the web services file system.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysisA file path is built from user input without being confined, so sequences like “../” let an attacker step outside the intended directory. That can expose configuration, credentials, or source code, and in the worst case lets an attacker write files where they shouldn't. A durable fix resolves and canonicalises the path, then rejects anything that escapes a known-safe base directory.
General guidance for the path traversal class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Secure Firewall Threat DefenseApplication
>= 6.2.3, < 6.2.3.16>= 6.3.0, < 6.3.0.6>= 6.4.0, < 6.4.0.8>= 6.5.0, < 6.5.0.4
Asa 5505 FirmwareOperating system
= 9.6\(4\)
Asa 5510 FirmwareOperating system
= 9.6\(4\)
Asa 5512 X FirmwareOperating system
= 9.6\(4\)
Asa 5515 X FirmwareOperating system
= 9.6\(4\)
Asa 5520 FirmwareOperating system
= 9.6\(4\)
Asa 5525 X FirmwareOperating system
= 9.6\(4\)
Asa 5540 FirmwareOperating system
= 9.6\(4\)CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped6.2.3.166.3.0.66.4.0.8
FTD: 6.2.3.16+, 6.3.0.6+, 6.4.0.8+, or 6.5.0.4+ (depending on current branch); ASA: contact Cisco TAC
- Identify the currently installed FTD version using 'show version' or through the management interface
- For FTD 6.2.x: Upgrade to version 6.2.3.16 or later
- For FTD 6.3.x: Upgrade to version 6.3.0.6 or later
- For FTD 6.4.x: Upgrade to version 6.4.0.8 or later
- For FTD 6.5.x: Upgrade to version 6.5.0.4 or later
- After upgrade, verify the new version is installed with 'show version'
- Note: For ASA devices on 9.6(4), the fixed version is not specified in the available advisory; contact Cisco TAC for ASA-specific patches
Generated from the published advisory — verify against the referenced sources before acting.
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-3187 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
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