

Unfortunately, scams are incredibly common with both fake recruiters (often using the name of a legitimate well known company, obviously without permission from said company) and fake candidates (sometimes using someone’s real identity).
No or very few legitimate recruiters will ask you to install something or run code they provide on your hardware with root privileges, but practically every scammer will. Once installed, they often act as rootkits or other malware, and monitor for credentials, crypto private keys, Internet banking passwords, confidential data belonging to other employers, VPN access that will allow them to install ransomware, and so on.
If we apply Bayesian statistics here with some made up by credible numbers - let’s call S the event that you were actually talking to a scam interviewer, and R the event that they ask you to install something which requires root equivalent access to your device. Call ¬S the event they are a legitimate interviewer, and ¬R the event they don’t ask you to install such a thing.
Let’s start with a prior: Pr(S) = 0.1 - maybe 10% of all outreach is from scam interviewers (if anything, that might be low).
Pr(¬S) = 1 - Pr(S) = 0.9.
Maybe estimate Pr(R | S) = 0.99 - almost all real scam interviewers will ask you to run something as root.
Pr(R | ¬S) = 0.01 - it would be incredibly rare for a non-scam interviewer to ask this.
Now by Bayes’ law, Pr(S | R) = Pr(R | S) * Pr(S) / Pr(R) = Pr(R | S) * Pr(S) / (Pr(R | S) * Pr(S) + Pr(R | ¬S) * Pr(¬S)) = 0.99 * 0.1 / (0.99 * 0.1 + 0.01 * 0.9) = 0.917
So even if we assume there was a 10% chance they were a scammer before they asked this, there is a 92% chance they are given they ask for you to run the thing.


I host my mail server on a VPS.
I suggest making sure you get DMARC / DKIM / SPF working, and having an anti-spam strategy (greylisting helps, but there are a few ASNs that just exist to send spam). Also make sure your IP is not on any public spam list.
The next problem you might face is that Microsoft and especially Google like to make it hard for anyone not using their services. With Microsoft, you fill in a form and jump through some hoops and they’ll start accepting your email enough to land it in spam. Unless you are regularly sending to Microsoft, it is hard to keep them accepting mail, but just sending to a free Hotmail address (owned and occasionally marked as read and deleted by you!) on cron is enough to keep occasional mail deliverable as long as none of your mail ever gets marked as spam. Google can be more of a pain to small email servers in terms of not landing in spam, but I think occasional reports of not spam will help you.
In terms of keeping down spam:
#!/bin/bash -e TEMPDIR=$(mktemp -d) trap 'rm -r "$TEMPDIR"' EXIT curl https://archive.routeviews.org/oix-route-views/oix-full-snapshot-latest.dat.bz2 -Lo "$TEMPDIR/snapshot.bz2" bzgrep -e " (15828|213035|400377|399471|210654|46573|211252|62904|135542|132372|36352|209641|7552|36352|12876|53667|138608|150393|60781|138607) i" $TEMPDIR/snapshot.bz2 | cut -d" " -f 3 | sort | uniq > $TEMPDIR/badranges iptables -N BAD_AS || true iptables -D INPUT -j BAD_AS || true iptables -A INPUT -j BAD_AS iptables -F BAD_AS for ROUTE in $(cat "$TEMPDIR/badranges"); do iptables -A BAD_AS -s $ROUTE -j DROP; doneNote that of the spam that gets through if you have the basic defences, it’s probably a similar level to big corporate hosted mail, so don’t let this deter you (I just hate spammers).