This person's threat model seems to be people who email him for a legitimate business reason, but see that he's away & take the opportunity to attack him? I just don't buy it - I think there is nothing wrong with always setting an autoresponder.
I'm getting pretty tired of this kind of thing. It's pretty clear to me that the infosec industry (within appsec and netsec at least, not risk and compliance) is bifurcated into two distinct groups. The first group consists of people who have real technical expertise, find serious vulnerabilities and make concrete suggestions about legitimate issues.
The second group, and the one I see more and more often (especially in bug bounties), consists of people who find ridiculous "security" "risks" in all manner of things. They're not appsec or netsec people but they think they're identifying actual security issues. Sometimes they point out superfluous implementation issues but more often than not they're writing articles like this - nitpicking the design of a thing without clarifying their threat model and with only a vague grounding in the potential risk of compromise.
I mean did we really need a security PSA about the risk of email autoresponders? Come on.
This lack of any concept of a threat model was precisely why his (considerable) effort was totally wasted and I can imagine similar "researchers" giving the industry as a whole a bad name.
Along the lines of "John and I had a payment planned, but he's out of the office, can you send it to [fake destination]?"
But, like other people have noted, you also have to weigh the chance of that happening in real life. It seems like the amount of planning on the attacker's part would be significant enough that if they could pull it off, they would have found easier targets by then.
If you're some outsider you don't know if that person is really unreachable or if their colleagues can easily reach them on Slack/send them a text/whatever if they have some important question.
And if you are internal/close enough to know their time off plans and that they're going backpacking in the Canadian Arctic, you didn't need the message to tell you they're out of office.
A guy in an Accounts Receivable role got phished. He went on a two week vacation, and bright-and-early on the first day he was out the phisher sent out emails as the vacationing AR person to a number of Customers advising them that remittance processing was being handled by a new third-party. They directed all the Customers to that third-party's "new" bank account. The attacker helpfully put a rule on the guy's Inbox to move new messages from every domain that the attacker emailed directly to "Deleted Items".
One of the Customers thought it seemed a bit fishy and called-in to confirm that very first day.
UPD: also, I guess any attacker could just assume that you're Out of Office at night time.
Impersonate the person out of town to escalate to their privilege level.
Imposter: "My password isn't working, can you help me reset it?" Yes, this is unlikely to to work in smaller orgs where you know people face to face. It is more likely to work as the org scales up in size (think enterprises with their own helpdesk).
Once you have email and/or other federated access, you have a toehold. Bonus points if you've cloned their work cell SIM or have rerouted SIP for their desk phone to keep them out of the loop. I have seen weaker phishing attacks on financial/accounting staff who have the authority to move millions of dollars of corporate funds.
EDIT:
> Whom the would-be attackers send this email to?
Phishing target
> Do they send this email from their own email address?
Throw away address or spoofed address from a familiar-to-the-business domain.
> Is there an assumption that sysadmin/support team will blindly reset a password on someone else's request?
This is one assumption.
> How do attackers bypass corporate VPN?
VPN access might not be required to obtain the level of access desired. Do all of your SaaS providers require 2FA? Your business bank accounts?
- Whom the would-be attackers send this email to?
- Do they send this email from their own email address?
- Is there an assumption that sysadmin/support team will blindly reset a password on someone else's request?
- How do attackers bypass corporate VPN?
This is only a few steps above Indian scammers taking remote control of users’ computers and convincing those users to send them hundreds of dollars of gift cards to prevent legal action by the IRS. Consider your average user, not the HN participant.
https://www.youtube.com/watch?v=YVqurfWzB-Q (Hacking Humans : Social Engineering Techniques and How to Protect Against Them - Stephen Haunts)
> Imposter: "My password isn't working, can you help me reset it?"
This doesn't have anything to do with being out of town or autoresponses.
This is not a hypothetical scenario, almost every year there is some idiot saying they going for vacation in those mini-interviews in the local newspaper and then they get their house broken into.
However the probability that someone does email you and is a burglar at the same time is extremely small.