H3C SSL VPN Username Enumeration

Title: H3C SSL VPN Username Enumeration
Advisory ID: ZSL-2022-5697
Type: Local/Remote
Impact: Exposure of Sensitive Information
Risk: (2/5)
Release Date: 12.02.2022
Summary
H3C SSL VPN is a secure VPN system based on SSL connections. It allows mobile employees to access corporate networks remotely in an easy and secure way. The H3C SSL VPN devices are a new generation of professional SSL VPN devices for enterprises. They can function as ingress gateways as well as proxy gateways of internal server clusters. The SecPath SSL VPN devices are for small-to medium-sized enterprises, while the SecBlade SSL VPN devices are for medium-sized enterprises.
Description
The weakness is caused due to the login script and how it verifies provided credentials. An attacker can use this weakness to enumerate valid users on the affected application via 'txtUsrName' POST parameter.
Vendor
Hangzhou H3C Technologies Co. | New H3C Technologies Co., Ltd. - https://www.h3c.com
Affected Version
N/A
Tested On
ssl vpn gateway HttpServer 1.1
Vendor Status
N/A
PoC
h3c_userenum.txt
Credits
Vulnerability discovered by Gjoko Krstic - <gjoko@zeroscience.mk>
References
[1] https://www.exploit-db.com/exploits/50742
[2] https://packetstormsecurity.com/files/165977/H3C-SSL-VPN-Username-Enumeration.html
[3] https://cxsecurity.com/issue/WLB-2022020072
[4] https://exchange.xforce.ibmcloud.com/vulnerabilities/219535
Changelog
[12.02.2022] - Initial release
[16.02.2022] - Added reference [1], [2], [3] and [4]
Contact
Zero Science Lab

Web: https://www.zeroscience.mk
e-mail: lab@zeroscience.mk