Get windows proxy username/password - windows

Question

I have an access to a preconfigured Windows XP 32-bit workstation.
It's under firewall and to get outside it uses http proxy server.
To get proxy settings I need host, port, username and password.
http: // username : password # server : port
I'm able to find the proxy url and port (from PAC - automatic config file),
but I don't know how to get username/password. Is there a way to read it somehow? At least username? I might get the admin rights.
Do you know any tool that can help?
I only found these MS docs about some methods to get proxy config connection, but I don't know how to determinate what's the provided credentials:
WinHttpGetIEProxyConfigForCurrentUser function
WINHTTP_CURRENT_USER_IE_PROXY_CONFIG structure
WinHttpGetProxyForUrl function
I've also found this lib, but it's rather for parsing PAC:
http://code.google.com/p/pacparser/

Answer 1

In windows you cannot get password.
To get connect throw a proxy you have to use SSPI, check libcurl, you can get a connected socket throw proxy, build it with enable-sspi and openssl.

Answer 2

Iterating on Fernando Sanchez's answer and Robert's comment, you need to authenticate via SSPI. In my case I've connected using NTLM using this link
With curl using ntlm :
curl.exe --proxy <proxy_name>:<proxy_port> --proxy-ntlm -U : https://www.google.com
Also to partially answer your question the -U : means from curl man page :
If you use a Windows SSPI-enabled curl binary and do either Negotiate
or NTLM authentication then you can tell curl to select the user name
and password from your environment by specifying a single colon with
this option: "-U :".
You can get the proxy name and port from the windows registry (regedit). Quote from Robert's comment:
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet
Settings]
It can be present either in a manual way using REG_SZ ProxyServer or using an autoconfiguration script using REG_SZ AutoConfigURL = https://<configuration_url>
If the curl command above fails with Failure when receiving data from the peer maybe you have a curl release without NTLM, SSPI or OpenSSL. Try with the latest curl release