CVE-2022-26532 in USG
Summary
by MITRE • 05/24/2022
A argument injection vulnerability in the 'packet-trace' CLI command of Zyxel USG/ZyWALL series firmware versions 4.09 through 4.71, USG FLEX series firmware versions 4.50 through 5.21, ATP series firmware versions 4.32 through 5.21, VPN series firmware versions 4.30 through 5.21, NSG series firmware versions 1.00 through 1.33 Patch 4, NXC2500 firmware version 6.10(AAIG.3) and earlier versions, NAP203 firmware version 6.25(ABFA.7) and earlier versions, NWA50AX firmware version 6.25(ABYW.5) and earlier versions, WAC500 firmware version 6.30(ABVS.2) and earlier versions, and WAX510D firmware version 6.30(ABTF.2) and earlier versions, that could allow a local authenticated attacker to execute arbitrary OS commands by including crafted arguments to the CLI command.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 05/29/2022
The vulnerability CVE-2022-26532 represents a critical argument injection flaw in the packet-trace command of Zyxel network security appliances across multiple series including USG, ZyWALL, ATP, VPN, NSG, NXC2500, NAP203, NWA50AX, WAC500, and WAX510D devices. This issue affects firmware versions ranging from 4.09 through 4.71 for USG/ZyWALL series up to various patch levels across different product lines, creating a widespread exposure across Zyxel's security portfolio. The vulnerability specifically resides in the command line interface processing mechanism where user-supplied arguments are not properly sanitized or validated before being passed to underlying operating system commands, creating a direct path for command injection attacks.
The technical implementation of this vulnerability stems from insufficient input validation within the packet-trace CLI command execution flow. When an authenticated local user provides crafted arguments to the packet-trace command, these inputs bypass proper sanitization controls and are directly incorporated into system command invocations without adequate escaping or filtering. This allows attackers to inject malicious command sequences that get executed with the privileges of the affected service account, typically root or administrative level access. The vulnerability aligns with CWE-77 and CWE-88 categories, representing command injection through improper argument handling, and maps to ATT&CK technique T1059.001 for command and scripting interpreter with the specific focus on the command line interface as an attack vector.
Operational impact of this vulnerability extends beyond simple privilege escalation to encompass full system compromise capabilities for local authenticated attackers. Successful exploitation enables adversaries to execute arbitrary operating system commands, potentially leading to complete system takeover, data exfiltration, or persistence mechanisms establishment. The local authentication requirement reduces the attack surface complexity but does not eliminate the risk, as many network security appliances have administrative accounts that could be compromised through credential theft, social engineering, or other attack vectors. Organizations running affected Zyxel appliances face significant risk of unauthorized access to their network infrastructure, potentially allowing attackers to manipulate firewall rules, intercept network traffic, or establish backdoors for continued access.
Mitigation strategies should prioritize immediate firmware updates to versions that address this vulnerability, with particular attention to the specific firmware versions mentioned in the CVE description. Network administrators must implement strict access controls and monitoring for CLI command usage, particularly for commands like packet-trace that handle user input. The principle of least privilege should be enforced by limiting local administrative access to only authorized personnel, while implementing multi-factor authentication for administrative accounts. Security monitoring should include detection of unusual command execution patterns and unauthorized CLI usage. Organizations should also consider network segmentation to limit the potential impact of a successful exploitation, ensuring that compromised appliances cannot be used as launching points for broader network attacks. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of affected firmware versions within the network infrastructure.