Security Resilience

CVE-2023-6764

Zyxel Atp100 Firmware 4.32 – 5.37

Published
20 February 2024
Modified
21 January 2025
Patch / advisory
View advisory
CVSS Score v3.1 8.1
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0089 59th percentile
Risk Priority 64 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-6764 is a high-severity Use of Externally-Controlled Format String (CWE-134) vulnerability in Zyxel Atp100 Firmware. Its CVSS base score is 8.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique LSASS Memory (T1003.001); ranked in the top 41% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

A format string vulnerability in a function of the IPSec VPN feature in Zyxel ATP series firmware versions from 4.32 through 5.37 Patch 1, USG FLEX series firmware versions from 4.50 through 5.37 Patch 1, USG FLEX 50(W) series firmware…

more

versions from 4.16 through 5.37 Patch 1, and USG20(W)-VPN series firmware versions from 4.16 through 5.37 Patch 1 could allow an attacker to achieve unauthorized remote code execution by sending a sequence of specially crafted payloads containing an invalid pointer; however, such an attack would require detailed knowledge of an affected device’s memory layout and configuration.

CWE(s)
CWE-134

Related Threats

MITRE ATT&CK Enterprise Techniques

T1003.001 LSASS Memory Credential Access
Adversaries may attempt to access credential material stored in the process memory of the Local Security Authority Subsystem Service (LSASS).
attack.mitre.org →
T1003.002 Security Account Manager Credential Access
Adversaries may attempt to extract credential material from the Security Account Manager (SAM) database either through in-memory techniques or through the Windows Registry where the SAM database is stored.
attack.mitre.org →
T1003.004 LSA Secrets Credential Access
Adversaries with SYSTEM access to a host may attempt to access Local Security Authority (LSA) secrets, which can contain a variety of different credential materials, such as credentials for service accounts.
attack.mitre.org →
T1003.007 Proc Filesystem Credential Access
Adversaries may gather credentials from the proc filesystem or `/proc`.
attack.mitre.org →
T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
attack.mitre.org →
T1016 System Network Configuration Discovery Discovery
Adversaries may look for details about the network configuration and settings, such as IP and/or MAC addresses, of systems they access or through information discovery of remote systems.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-6399Same product: Zyxel Atp100
CVE-2023-33011Same product: Zyxel Usg Flex 100
CVE-2023-22923Same vendor: Zyxel
CVE-2023-6397Same product: Zyxel Atp100
CVE-2023-27990Same product: Zyxel Atp100
CVE-2023-27991Same product: Zyxel Atp100
CVE-2023-22917Same product: Zyxel Atp100
CVE-2023-6398Same product: Zyxel Atp100
CVE-2023-33010Same product: Zyxel Atp100
CVE-2023-33009Same product: Zyxel Atp100

Affected Assets

zyxel
atp100 firmware
5.37 · 4.32 — 5.37
zyxel
atp100w firmware
5.37 · 4.32 — 5.37
zyxel
atp200 firmware
5.37 · 4.32 — 5.37
zyxel
atp500 firmware
5.37 · 4.32 — 5.37
zyxel
atp700 firmware
5.37 · 4.32 — 5.37
zyxel
atp800 firmware
5.37 · 4.32 — 5.37
zyxel
usg flex 100 firmware
5.37 · 4.50 — 5.37
zyxel
usg flex 100ax firmware
5.37 · 4.50 — 5.37
zyxel
usg flex 100h firmware
5.37 · 4.50 — 5.37
zyxel
usg flex 100w firmware
5.37 · 4.50 — 5.37
+11 more product configuration(s) — see NVD for full list

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and static analysis can discover format-string vulnerabilities before deployment.

SI-10 Information Input Validation good match

Input validation can reject or sanitize externally supplied format strings before they reach formatting functions.

SA-15 Development Process, Standards, and Tools partial match

Secure development standards and tools can mandate use of static format strings or safe formatting APIs.

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.

ID.RA-01 partial match
blocks

Vulnerability identification can discover existing format-string flaws but does not prevent their introduction.

PR.PS-06 partial match
blocks

Secure SDLC practices directly prevent external format strings via code review, static analysis, and safe APIs.

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.

A.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.8.10 Information deletion partial match
removes

References