Cyber Resilience

CVE-2020-3452

Path Traversal in Cisco Adaptive Security Appliance Software 9.6 – 9.6.4.42

CISA KEVActive ExploitationEUVD ExploitedPublic PoCPath Traversal
Published
22 July 2020
Modified
11 August 2026
KEV Added
03 November 2021
Patch / advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS Score 0.99 100.0th percentile
Risk Priority 84 floored blend · peak EPSS

Summary

CVE-2020-3452 is a high-severity Improper Input Validation (CWE-20) vulnerability in Cisco Adaptive Security Appliance Software. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 0.0% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

A vulnerability tracked as CVE-2020-3452 exists in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software. It stems from insufficient input validation of URLs in HTTP requests and is present when the device is configured with WebVPN or AnyConnect features, which enable the web services file system. The flaw is assigned CWE-20 and CWE-22 and carries a CVSS 3.1 score of 7.5.

An unauthenticated remote attacker can exploit the issue by sending a crafted HTTP request containing directory traversal sequences. Successful exploitation grants the ability to read arbitrary files stored in the web services file system, although ASA or FTD system files and underlying operating system files cannot be accessed.

The official Cisco Security Advisory cisco-sa-asaftd-ro-path-KJuQhB86 details the vulnerability and is referenced alongside multiple public exploit proofs of concept published on PacketStorm Security for affected releases including 9.6, 9.11, 9.14, and FTD 6.6.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

A 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 read sensitive files on a targeted system.…

more

The vulnerability is due to a lack of proper input validation of URLs in HTTP requests processed by an affected device. An attacker could exploit this vulnerability by sending a crafted HTTP request containing directory traversal character sequences to an affected device. A successful exploit could allow the attacker to view arbitrary files within the web services file system on the targeted device. The web services file system is enabled when the affected device is configured with either WebVPN or AnyConnect features. This vulnerability cannot be used to obtain access to ASA or FTD system files or underlying operating system (OS) files.

CWE(s)
KEV Date Added
03 November 2021

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1036.001 Invalid Code Signature Stealth
Adversaries may attempt to mimic features of valid code signatures to increase the chance of deceiving a user, analyst, or tool.
T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2018-0296Same product: Cisco Adaptive Security Appliance Softwareboth on KEV
CVE-2020-3239Same vendor: Cisco
CVE-2020-3247Same vendor: Cisco
CVE-2020-3248Same vendor: Cisco
CVE-2020-3251Same vendor: Cisco
CVE-2020-3187Same product: Cisco Adaptive Security Appliance Software
CVE-2015-0666Same vendor: Ciscoboth on KEV
CVE-2026-20262Same vendor: Ciscoboth on KEV
CVE-2022-20775Same vendor: Ciscoboth on KEV
CVE-2020-8195Shared CWE-20, CWE-22both on KEV

Affected Assets

cisco
adaptive security appliance software
9.6 — 9.6.4.42 · 9.8 — 9.8.4.20 · 9.9 — 9.9.2.74
cisco
secure firewall threat defense
6.2.3 — 6.2.3.16 · 6.3.0 — 6.3.0.6 · 6.4.0 — 6.4.0.10

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 6 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V5.3.2

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-20 CWE-22

Directly implements checks on information inputs to reject invalid data before processing.

addresses: CWE-20

Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.

addresses: CWE-20

Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.

addresses: CWE-20

Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require and enforce input validation during development.

PR.PS-02 partial match
prevents

Patching/maintenance can remediate known path-traversal flaws in deployed software (partial prevention of exploitability) but does nothing to stop the coding defect from being introduced in the first place.

PR.AA-05 none match
prevents

PR.AA-05 defines and reviews access policies but does not address code-level pathname neutralization, so neither direction prevents CWE-22.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Testing against a defined set of requirements and using code review plus vulnerability scanning forces validation of inputs and handling of unanticipated conditions, reducing the chance that malformed data will be accepted.

prevents

Secure-coding guidelines and mandatory security testing (including code scans) compel developers to validate and sanitize inputs at design and implementation time, lowering the incidence of malformed or malicious data reaching downstream components.

prevents

Mandating input controls that include integrity checks and input validation ensures that untrusted data is examined before use, blocking the root cause of many injection and malformed-data weaknesses.

prevents

Security-by-design principles explicitly call for data validation and sanitization at every layer, reducing the chance that malformed or malicious input will be processed without scrutiny.

prevents

Requiring language-specific secure coding standards, peer review, SAST and documented mitigation of common programming errors forces validation of all inputs before they are trusted.

mitigates

Information access restriction limits which files an application may read or write.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

RHEL 8 (1 rule)
  • V-230265 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-20

References