cargo deny: 'NTLM' authentication is not supported

What OS is this on?

ubuntu0.20.04.1 behind a corp proxy with correct http_proxy, https_proxy and no_proxy set. Other cargo commands work fine. I noticed the same behavior with cargo audit, the error message is just slightly different:

cargo audit
error: couldn't fetch advisory database: git operation failed: 'NTLM' authentication is not supported; class=Http (34)

I tried to exec rm -rf ~/.cargo/advisory-db beforehand as reported in some old issues but that does not help in my case.

You can try adding this to your config to see if that resolves this issue.

[advisories]
git-fetch-with-cli = true

Otherwise you could add a PR to improve the setup of the libgit2 authentication at https://github.com/EmbarkStudios/cargo-deny/blob/824c2d1304086861ce66b0386d4852d2fab42b81/src/advisories/helpers.rs#L217, unfortunately scenarios such as yours rely on contributions from people who actually have a repro for the issue.

Setting

[advisories]
git-fetch-with-cli = true

leads to

$ cargo-deny check advisories
Cloning into '/home/runner/.cargo/advisory-db/github.com-2f857891b7f43c59'...
fatal: unable to access 'https://github.com/rustsec/advisory-db/': Received HTTP code 407 from proxy after CONNECT
2022-07-15 14:10:05 [ERROR] failed to open advisory database: failed to resolve path '/home/runner/.cargo/advisory-db/github.com-2f857891b7f43c59': No such file or directory; class=Os (2); code=NotFound (-3

Ok, well in that case you'd need to make a PR to either improve the libgit2 authentication setup I mentioned above, or the CLI path if it is easier, as I have no idea why git itself would fail if it works in other scenarios.

Ok, how is that related to the CLI path?

It's not, I'm saying you could improve either path depending on which is easier for you.