Zyxel security advisory for cleartext storage of information vulnerability

Zyxel_May

CVE: CVE-2021-35036

Summary

Zyxel is releasing patches addressing a cleartext storage of information vulnerability in its products. Users are advised to install the patches for optimal protection.

What is the vulnerability?

The cleartext storage of information vulnerability is due to a CGI program lacking proper protection of the device’s login privilege and TR-069 configuration. The vulnerability cannot be exploited unless the attacker can first be successfully authenticated and log in to the device’s management interface. The TR-069 protocol is not enabled by default in the generic version of the firmware; therefore, it cannot be exploited by attackers.

What versions are vulnerable—and what should you do?

After a thorough investigation, we have identified the vulnerable products that are within their vulnerability support period, with their firmware patches shown in the table below.

Product	Affected model	Patch availability*
DSL/Ethernet CPE	VMG3625-T50B	Customized firmware version V5.50(ABTL.0)b2r EMEA: V5.50(ABPM.7)C0 Central America: V5.50(ACCR.0)b4
	VMG3927-T50K	V5.50(ABOM.8)C0
	VMG8623-T50B	V5.50(ABPM.7)C0
	VMG8825-T50K	V5.50(ABOM.8)C0
	EMG3525-T50B	V5.50(ABPM.7)C0
	EMG5523-T50B	V5.50(ABPM.7)C0
	EMG5723-T50K	V5.50(ABOM.8)C0
	DX3301-T0	V5.50(ABVY.3)C0
	DX5401-B0	V5.17(ABYO.2)C0
	EX5401-B0	V5.17(ABYO.2)C0
	EX5501-B0	V5.17(ABRY.3)C0
Fiber ONT	AX7501-B Series	V5.17(ABPC.2)C0
	EP240P	V5.40(ABVH.0)C0a03
	PMG5617GA	V5.40(ABNA.2)C0
	PMG5622GA	V5.40(ABNB.2)C0
	PMG5317-T20B	V5.40(ABKI.4)C0
	PMG5617-T20B2	V5.41(ACBB.1)C0
	PM7300-T0	V5.42(ACBC.1)C0
5G NR/4G LTE CPE	LTE3301-PLUS	V1.00(ABQU.6)C0 in Dec. 2022
	LTE5388-M804	V1.00(ABSQ.4)C0 in Dec. 2022
	LTE5388-S905	V1.00(ABVI.6)C0 in Dec. 2022
	LTE5398-M904	V1.00(ABQV.2)C0 in Dec. 2022
	LTE7240-M403	V2.00(ABMG.6)C0 in Dec. 2022
	LTE7461-M602	V2.00(ABQN.6)C0 in Dec. 2022
	LTE7480-S905	V2.00(ABQT.6)C0 in Dec. 2022
	LTE7480-M804	V1.00(ABRA.6)C0 in Dec. 2022
	LTE7485-S905	V1.00(ABVN.6)C0 in Dec. 2022
	LTE7490-M804	V1.00(ABQY.5)C0 in Dec. 2022
	NR5101	V1.00(ABVC.6)C0 in Dec. 2022
	NR7101	V1.00(ABUV.7)C0 in Dec. 2022
	NR7102	V1.00(ABYD.2)C0 in Dec. 2022

*Please contact your sales representative or support team for the file.

For ISPs, please contact your Zyxel sales or service representatives for further details.

For end-users who received your Zyxel device from an ISP, we recommend you reach out to the ISP’s support team directly, as the device may have custom-built settings.

For end-users who purchased the Zyxel devices on your own, please contact your local Zyxel support team for the new firmware file to ensure optimal protection, or visit our forum for further assistance.

Got a question?

Please contact your local service rep or visit Zyxel’s Community  for further information or assistance.

Acknowledgment

Thanks to M.nageh for reporting the issue to us.

Revision history

2022-09-27: Initial release