Entries Tagged "email"

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E-Mailing Private HTTPS Keys

I don’t know what to make of this story:

The email was sent on Tuesday by the CEO of Trustico, a UK-based reseller of TLS certificates issued by the browser-trusted certificate authorities Comodo and, until recently, Symantec. It was sent to Jeremy Rowley, an executive vice president at DigiCert, a certificate authority that acquired Symantec’s certificate issuance business after Symantec was caught flouting binding industry rules, prompting Google to distrust Symantec certificates in its Chrome browser. In communications earlier this month, Trustico notified DigiCert that 50,000 Symantec-issued certificates Trustico had resold should be mass revoked because of security concerns.

When Rowley asked for proof the certificates were compromised, the Trustico CEO emailed the private keys of 23,000 certificates, according to an account posted to a Mozilla security policy forum. The report produced a collective gasp among many security practitioners who said it demonstrated a shockingly cavalier treatment of the digital certificates that form one of the most basic foundations of website security.

Generally speaking, private keys for TLS certificates should never be archived by resellers, and, even in the rare cases where such storage is permissible, they should be tightly safeguarded. A CEO being able to attach the keys for 23,000 certificates to an email raises troubling concerns that those types of best practices weren’t followed.

I am croggled by the multiple layers of insecurity here.

BoingBoing post.

Posted on March 13, 2018 at 6:31 AM • View Comments

E-Mail Tracking

Good article on the history and practice of e-mail tracking:

The tech is pretty simple. Tracking clients embed a line of code in the body of an email­—usually in a 1×1 pixel image, so tiny it’s invisible, but also in elements like hyperlinks and custom fonts. When a recipient opens the email, the tracking client recognizes that pixel has been downloaded, as well as where and on what device. Newsletter services, marketers, and advertisers have used the technique for years, to collect data about their open rates; major tech companies like Facebook and Twitter followed suit in their ongoing quest to profile and predict our behavior online.

But lately, a surprising­—and growing­—number of tracked emails are being sent not from corporations, but acquaintances. “We have been in touch with users that were tracked by their spouses, business partners, competitors,” says Florian Seroussi, the founder of OMC. “It’s the wild, wild west out there.”

According to OMC’s data, a full 19 percent of all “conversational” email is now tracked. That’s one in five of the emails you get from your friends. And you probably never noticed.

I admit it’s enticing. I would very much like the statistics that adding trackers to Crypto-Gram would give me. But I still don’t do it.

Posted on December 13, 2017 at 6:14 AM • View Comments

Cybercriminals Infiltrating E-Mail Networks to Divert Large Customer Payments

There’s a new criminal tactic involving hacking an e-mail account of a company that handles high-value transactions and diverting payments. Here it is in real estate:

The scam generally works like this: Hackers find an opening into a title company’s or realty agent’s email account, track upcoming home purchases scheduled for settlements—the pricier the better—then assume the identity of the title agency person handling the transaction.

Days or sometimes weeks before the settlement, the scammer poses as the title or escrow agent whose email accounts they’ve hijacked and instructs the home buyer to wire the funds needed to close—often hundreds of thousands of dollars, sometimes far more—to the criminals’ own bank accounts, not the title or escrow company’s legitimate accounts. The criminals then withdraw the money and vanish.

Here it is in fine art:

The fraud is relatively simple. Criminals hack into an art dealer’s email account and monitor incoming and outgoing correspondence. When the gallery sends a PDF invoice to a client via email following a sale, the conversation is hijacked. Posing as the gallery, hackers send a duplicate, fraudulent invoice from the same gallery email address, with an accompanying message instructing the client to disregard the first invoice and instead wire payment to the account listed in the fraudulent document.

Once money has been transferred to the criminals’ account, the hackers move the money to avoid detection and then disappear. The same technique is used to intercept payments made by galleries to their artists and others. Because the hackers gain access to the gallery’s email contacts, the scam can spread quickly, with fraudulent emails appearing to come from known sources.

I’m sure it’s happening in other industries as well, probably even with business-to-business commerce.

EDITED TO ADD (11/14): Brian Krebs wrote about this in 2014.

Posted on November 7, 2017 at 6:37 AM • View Comments

E-Mail Tracking

Interesting survey paper: on the privacy implications of e-mail tracking:

Abstract: We show that the simple act of viewing emails contains privacy pitfalls for the unwary. We assembled a corpus of commercial mailing-list emails, and find a network of hundreds of third parties that track email recipients via methods such as embedded pixels. About 30% of emails leak the recipient’s email address to one or more of these third parties when they are viewed. In the majority of cases, these leaks are intentional on the part of email senders, and further leaks occur if the recipient clicks links in emails. Mail servers and clients may employ a variety of defenses, but we analyze 16 servers and clients and find that they are far from comprehensive. We propose, prototype, and evaluate a new defense, namely stripping tracking tags from emails based on enhanced versions of existing web tracking protection lists.

Blog post on the research.

Posted on October 3, 2017 at 6:45 AM • View Comments

Journalists Generally Do Not Use Secure Communication

This should come as no surprise:

Alas, our findings suggest that secure communications haven’t yet attracted mass adoption among journalists. We looked at 2,515 Washington journalists with permanent credentials to cover Congress, and we found only 2.5 percent of them solicit end-to-end encrypted communication via their Twitter bios. That’s just 62 out of all the broadcast, newspaper, wire service, and digital reporters. Just 28 list a way to reach them via Signal or another secure messaging app. Only 22 provide a PGP public key, a method that allows sources to send encrypted messages. A paltry seven advertise a secure email address. In an era when anything that can be hacked will be and when the president has declared outright war on the media, this should serve as a frightening wake-up call.

[…]

When journalists don’t step up, sources with sensitive information face the burden of using riskier modes of communication to initiate contact­—and possibly conduct all of their exchanges­—with reporters. It increases their chances of getting caught, putting them in danger of losing their job or facing prosecution. It’s burden enough to make them think twice about whistleblowing.

I forgive them for not using secure e-mail. It’s hard to use and confusing. But secure messaging is easy.

Posted on August 31, 2017 at 6:52 AM • View Comments

Giving Up on PGP

Filippo Valsorda wrote an excellent essay on why he’s giving up on PGP. I have long believed PGP to be more trouble than it is worth. It’s hard to use correctly, and easy to get wrong. More generally, e-mail is inherently difficult to secure because of all the different things we ask of it and use it for.

Valsorda has a different complaint, that its long-term secrets are an unnecessary source of risk:

But the real issues, I realized, are more subtle. I never felt confident in the security of my long-term keys. The more time passed, the more I would feel uneasy about any specific key. Yubikeys would get exposed to hotel rooms. Offline keys would sit in a far away drawer or safe. Vulnerabilities would be announced. USB devices would get plugged in.

A long-term key is as secure as the minimum common denominator of your security practices over its lifetime. It’s the weak link.

Worse, long-term key patterns, like collecting signatures and printing fingerprints on business cards, discourage practices that would otherwise be obvious hygiene: rotating keys often, having different keys for different devices, compartmentalization. Such practices actually encourage expanding the attack surface by making backups of the key.

Both he and I favor encrypted messaging, either Signal or OTR.

EDITED TO ADD (1/13): More PGP criticism.

Posted on December 16, 2016 at 5:36 AM • View Comments

Yahoo Scanned Everyone's E-mails for the NSA

News here and here.

Other companies have been quick to deny that they did the same thing, but I generally don’t believe those carefully worded statements about what they have and haven’t done. We do know that the NSA uses bribery, coercion, threat, legal compulsion, and outright theft to get what they want. We just don’t know which one they use in which case.

EDITED TO ADD (10/7): More news. This and this, too.

EDITED TO ADD (10/17): A related story.

Posted on October 6, 2016 at 1:58 PM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.