CVE-2023-33012

published 2023-07-17

CVE-2023-33012: A command injection vulnerability in the configuration parser of the Zyxel ATP series firmware versions 5.10 through 5.36 Patch 2, USG FLEX series firmware…

Priority P2 68 high 8.8 CVSS 3.1

AV A AC L PR N UI N S U C H I H A H

EXPLOIT

A command injection vulnerability in the configuration parser of the Zyxel ATP series firmware versions 5.10 through 5.36 Patch 2, USG FLEX series firmware versions 5.00 through 5.36 Patch 2, USG FLEX 50(W) series firmware versions 5.10 through 5.36 Patch 2, USG20(W)-VPN series firmware versions 5.10 through 5.36 Patch 2, and VPN series firmware versions 5.00 through 5.36 Patch 2, could allow an unauthenticated, LAN-based attacker to execute some OS commands by using a crafted GRE configuration when the cloud management mode is enabled.

Affected

27 ranges · showing 25

Vendor	Product	Version range	Fixed in
zyxel	atp_series_firmware	—	—
zyxel	usg20_vpn_series_firmware	—	—
zyxel	usg_20w-vpn_firmware	>= 5.10 < 5.37	5.37
zyxel	usg_2200-vpn_firmware	>= 5.00 < 5.37	5.37
zyxel	usg_flex_100_firmware	>= 5.00 < 5.37	5.37
zyxel	usg_flex_100w_firmware	>= 5.00 < 5.37	5.37
zyxel	usg_flex_200_firmware	>= 5.00 < 5.37	5.37
zyxel	usg_flex_500_firmware	>= 5.00 < 5.37	5.37
zyxel	usg_flex_50_firmware	>= 5.00 < 5.37	5.37
zyxel	usg_flex_50_series_firmware	—	—
zyxel	usg_flex_50w_firmware	>= 5.00 < 5.37	5.37
zyxel	usg_flex_700_firmware	>= 5.00 < 5.37	5.37
zyxel	usg_flex_series_firmware	—	—
zyxel	vpn_series_firmware	—	—
zyxel	zywall_atp100_firmware	>= 5.10 < 5.37	5.37
zyxel	zywall_atp100w_firmware	>= 5.10 < 5.37	5.37
zyxel	zywall_atp200_firmware	>= 5.10 < 5.37	5.37
zyxel	zywall_atp500_firmware	>= 5.10 < 5.37	5.37
zyxel	zywall_atp700_firmware	>= 5.10 < 5.37	5.37
zyxel	zywall_atp800_firmware	>= 5.10 < 5.37	5.37
zyxel	zywall_vpn100_firmware	>= 5.00 < 5.37	5.37
zyxel	zywall_vpn2s_firmware	>= 5.00 < 5.37	5.37
zyxel	zywall_vpn300_firmware	>= 5.00 < 5.37	5.37
zyxel	zywall_vpn50_firmware	>= 5.00 < 5.37	5.37
zyxel	zywall_vpn_100_firmware	>= 5.00 < 5.37	5.37

Detection & IOCs extracted from sources · hover to see the quote

filename parse_config.py↗

path modules/exploits/linux/http/zyxel_parse_config_rce.rb↗

• → Monitor for crafted GRE configuration payloads submitted to Zyxel devices operating in cloud management mode, which may contain injected OS commands within the configuration parser. ↗
• → The attack originates from the LAN segment and requires no authentication; alert on unexpected OS command execution spawned from the configuration parser process (parse_config.py) on Zyxel ATP, USG FLEX, USG FLEX 50(W), USG20(W)-VPN, and VPN series devices. ↗
• → A public Metasploit module exists for this CVE targeting the HTTP service on Linux-based Zyxel devices; monitor for exploitation attempts matching the module path linux/http/zyxel_parse_config_rce. ↗

• · Exploitation requires cloud management mode to be enabled on the target device; devices not in cloud management mode are not affected by this attack vector. ↗
• · The Metasploit module was not tested against a real Zyxel device; it was validated only against a mock environment, so detection fidelity in production may vary. ↗
• · Affected firmware version ranges differ per product line (ATP 5.10–5.36 Patch 2; USG FLEX 5.00–5.36 Patch 2; USG FLEX 50(W) 5.10–5.36 Patch 2; USG20(W)-VPN 5.10–5.36 Patch 2; VPN 5.00–5.36 Patch 2); ensure version scoping is accurate before applying detections. ↗

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