Zyxel security advisory for cleartext storage of information vulnerability

CVEs: 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.

Affected series/modelsPatch availability*
DSL/Ethernet CPE
VMG3625-T50BCustomized firmware version V5.50(ABTL.0)b2r
EMEA: V5.50(ABPM.7)C0
Central America: V5.50(ACCR.0)b4
VMG3927-T50KV5.50(ABOM.8)C0
VMG8623-T50BV5.50(ABPM.7)C0
VMG8825-T50KV5.50(ABOM.8)C0
EMG3525-T50BV5.50(ABPM.7)C0
EMG5523-T50BV5.50(ABPM.7)C0
EMG5723-T50KV5.50(ABOM.8)C0
DX3301-T0V5.50(ABVY.3)C0
DX5401-B0V5.17(ABYO.2)C0
EX5401-B0V5.17(ABYO.2)C0
EX5501-B0V5.17(ABRY.3)C0
5G NR/4G LTE CPE
LTE3301-PLUSV1.00(ABQU.6)C0 in Dec. 2022
LTE5388-M804V1.00(ABSQ.4)C0 in Dec. 2022
LTE5388-S905V1.00(ABVI.6)C0 in Dec. 2022
LTE5398-M904V1.00(ABQV.2)C0 in Dec. 2022
LTE7240-M403V2.00(ABMG.6)C0 in Dec. 2022
LTE7461-M602V2.00(ABQN.6)C0 in Dec. 2022
LTE7480-S905V2.00(ABQT.6)C0 in Dec. 2022
LTE7480-M804V1.00(ABRA.6)C0 in Dec. 2022
LTE7485-S905V1.00(ABVN.6)C0 in Dec. 2022
LTE7490-M804V1.00(ABQY.5)C0 in Dec. 2022
NR5101V1.00(ABVC.6)C0 in Dec. 2022
NR7101V1.00(ABUV.7)C0 in Dec. 2022
NR7102V1.00(ABYD.2)C0 in Dec. 2022
Fiber ONT
AX7501-B SeriesV5.17(ABPC.2)C0
EP240PV5.40(ABVH.0)C0a03
PMG5617GAV5.40(ABNA.2)C0
PMG5622GAV5.40(ABNB.2)C0
PMG5317-T20BV5.40(ABKI.4)C0
PMG5617-T20B2V5.41(ACBB.1)C0
PM7300-T0V5.42(ACBC.1)C0
*Please contact your sales representative or support team for the file.

 

Got a question?

If you are an ISP with customized models, please contact your Zyxel sales or service representative for further information or assistance. For end-user who acquired your Zyxel device from an ISP, please reach out to the ISP’s support team directly, as the device may have custom-built settings.

 

Acknowledgment

Thanks to Mina Nageh Salama for reporting the issue to us.

 

Revision history

2022-09-27: Initial release