Escaping special characters in proxy auth passwords in vCenter

EDIT: It seems that his was fixed in vCenter 7.0 U3.

While debugging a vCener Lifecycle Manager, which was unable to download updates, I’ve stumbled over a weird behaviour, which is (IMHO) by design.

Some of you might use a proxy server. And some of you might use a proxy server which requires credentials. In my case, my customer uses a Sophos SG appliance as a web proxy server with authentication. The customer creaded a user with a complex password. But I was unable to get a working internet connection.

Image by Ed Webster from Pixabay 

I played a bit with curl on the bash of the vCenter. The proxy settings are stored under /etc/sysconfig/proxy. These settings are used to populate the http_proxy and https_proxy environment variable. It’s important to know, that the credentials stored in the /etc/sysconfig/proxy are encoded with the percent-encoding, also known as URL encoding. So someone with root access can grab credentials from these file.

But then I noticed something weird. I set the http_proxy variable manually with

http://username:password@proxy.domain.tld:8080

and I got this error:

-bash: !": event not found

Okay… there was a ! in the password and the BASH tried to execute the part behind the !. But it was part of the password, so I had to tell the BASH that it has to take this literally.

I escaped the ! in the password with a \. And to my surprise: The vCenter was able to download updates. I decoded the percent-encoded string in the /etc/sysconfig/poxy and found the escaped ! (\!). For example. Instead of Passw0rd! I had to enter Passw0rd\! in the password field.

Long story short: Use a password without special characters, otherwise escape them, because the password is stored in BASH variables.

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Patrick Terlisten
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