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Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘Security’ Category

SSL certificates – not optional | Open Query Pty Ltd

Posted by jpluimers on 2020/09/04

Some tips on using the certbot for Let’s Encrypt and the support for wildcard certificates through DNS updates: [WayBack] SSL certificates – not optional | Open Query Pty Ltd

–jeroen

Posted in Encryption, HTTPS/TLS security, Let's Encrypt (letsencrypt/certbot), Power User, Security | Leave a Comment »

Some banking apps are not so privacy friendly

Posted by jpluimers on 2020/09/01

Some baking apps want a lot of permissions, including privacy sensitive ones.

Maybe they should split themselves in a small, non-intrusive app that allows payment confirmation, and fatter (hopefully less intrusive than now) app for account management.

For now, I try to avoid these apps as they are single points of failures.

ING had a great TAN code system on paper. It hardly had any side-channel attack vectors, and by putting some copies in geographically distinct locations, you had good and safe back-ups too.

It looks like the successor is a single point of failure: only one scanner device per account holder is possible.

Let’s see what the future will bring.

Related:

 

–jeroen

Posted in LifeHacker, Power User, Security | Leave a Comment »

DIY electronic RFID Door Lock with Battery Backup – CodeProject

Posted by jpluimers on 2020/08/26

On my list: check if Mifare Desfire cards are still secure enough for something like a [WayBackDIY electronic RFID Door Lock with Battery Backup – CodeProject.

Via: [WayBack] Lots of interesting info on RFID use. https://www.codeproject.com/Articles/1096861/DIY-electronic-RFID-Door-Lock-with-Battery-Backup – Lars Fosdal – Google+

–jeroen

Posted in Development, Hardware Development, LifeHacker, Power User, Security | Leave a Comment »

Password hashing on client side is insecure · Issue #44 · meteor/meteor-feature-requests · GitHub and some bcrypt notes

Posted by jpluimers on 2020/08/26

Some interesting bits from [WayBack] Password hashing on client side is insecure · Issue #44 · meteor/meteor-feature-requests · GitHub by tysonclugg:

Stop with the client side hashing – it’s security theatrics. Submit plain text passwords over TLS. The focus should be on having TLS enabled by default, and making sure the server has a sufficient amount of cryptographic work-factor during authentication to render brute-force attacks ineffective (eg: use server-side bcrypt).

Honestly, javascript password shenanigans in the browser is as dumb as backing up HOTP/TOTP secrets from your 2FA app in case you lose your phone. Hint: that changes “something you have” into “something you know”, authenticating with two things you know is single factor authentication. And yet, a group of “smart people” created an app that allows just that. Don’t be another one of those “smart people”.

If you’re still unsure about ditching client-side password hashing, have a read on what others have said:

  1. https://www.nccgroup.trust/us/about-us/newsroom-and-events/blog/2011/august/javascript-cryptography-considered-harmful/
  2. http://thisinterestsme.com/client-side-hashing-secure/
  3. https://security.stackexchange.com/questions/53594/why-is-client-side-hashing-of-a-password-so-uncommon
  4. https://cybergibbons.com/security-2/stop-doing-client-side-password-hashing/
  5. https://www.reddit.com/r/crypto/comments/375lor/is_client_side_hashing_of_passwords_viable_to/
    5.1. One of the comments specifically mentions SRP, but goes on to say:

You’ll probably be interested in the Secure Remote Password protocol (SRP). It uses a variant of the Diffie-Hellman key negotiation protocol to simultaneously authenticate the client with the server, the server with the client, and establish a session key for sending secrets between the client and server. It’s not very useful with web applications, because you still have to trust the encrypted channel to deliver the right version of the JavaScript to manage the communication. It could be useful for other client/server applications, where the client application can be verified and isn’t retransmitted every session.

If you’re still not convinced after reading all of the above, I’d suggest you contact a notable cryptographer for further advice. Prof. David A. Wagner might be a good choice.

Meanwhile, client side password hashing hinders upgrades to the password hashing scheme, and nothing has been done.

Hindering, not preventing. Of course you can send many hashed variants of the password from the client to the server to account for whichever legacy hash exists in the DB, but in my that weakens the system by allowing many hashes to be submitted simultaneously (or in short order) with no work factor. The result is that brute forcing an account becomes much easier.

and in [WayBack] Password hashing on client side is insecure · Issue #4363 · meteor/meteor · GitHub:

On compatibility (the reason I visited the Meteor password hashing code in the first place), upgrading to new hashing algorithms (which MUST be done from time to time) is much easier if the plaintext password is passed to the server, and transparent to the client as no new API is required to handle the case of upgrading from an old hash to a new hash. The generally accepted means of storing hashes is “$” such as “pbkdf2_sha256$15000$ZLpQISRxzhY0$fxrQcKxhkG//nHg10NrkulhvWkAqWbWeQg4QeD7c59E=
This is a PBKDF2 hash for the password “pass” which includes the number of rounds, the salt and the resultant hash ready to be verified and upgraded if required, for example by increasing the number of rounds from 150000 to 250000, or ready to be swapped to a different algorithm altogether (eg: pbkdf2_sha512).

NIST in 2017 on key derivation functions:

In June 2017, NIST issued a new revision of their digital authentication guidelines, NIST SP 800-63B-3,[12]:5.1.1.1 stating that: “Verifiers SHALL store memorized secrets [i.e. passwords] in a form that is resistant to offline attacks. Memorized secrets SHALL be salted and hashed using a suitable one-way key derivation function. Key derivation functions take a password, a salt, and a cost factor as inputs then generate a password hash. Their purpose is to make each password guessing trial by an attacker who has obtained a password hash file expensive and therefore the cost of a guessing attack high or prohibitive.” and that “The salt SHALL be at least 32 bits in length and be chosen arbitrarily so as to minimize salt value collisions among stored hashes.”

It looks like Argon2 is better than bcrypt and PBKDF2_SHA512. The 2017 hashing speed table:

sha1: 68.000.000.000 hash/s
sha256: 23.000.000.000 hash/s
sha512: 8.600.000.000 hash/s
sha3: 6.500.000.000 hash/s
bcrypt(5): 105.700 hash/s(for work factor 15 it’s {\displaystyle {\frac {105700}{2^{15-5}}}=103} hash/sec)
sha256crypt: 3.100.000 hash/s
And with stretching:
pbkdf2-sha1(1000 r): 26.000.000 hash/s
pbkdf2-sha256: 9.400.000 hash/s
pbkdf2-sha512: 3.400.000 hash/s

Also, one commenter mentioned that using future telling skills we expect that hash values improve 55% annually, which is exciting and scary at once. —grin 13:51, 10 October 2017 (UTC)

The cost is confirmed at [WayBack] bcrypt cost 10/12/14 brute force time? – Information Security Stack Exchange, so in 2020 it should be somewhere around the 12-14 range.

Moore’s law does not fully apply any more for single core performance, but there are other potential optimisations, and it is unclear how future hash attacks will improve, so it is better to use a mini-bench mark to calculate a good cost, see:

Delphi implementations:

Via:

Further reading:

–jeroen

Posted in Development, Hashing, Power User, Security, Software Development | Leave a Comment »

Roderick Gadellaa auf Twitter: “@ingnl Ik begrijp dat jullie gaan stoppen met TAN codes. Juich ik toe, 2FA met sms is behoorlijk lek. Maar nu moet ik jullie app gaan gebruiken. Ik werp 1 blik op de permissions die jullie app wil en denk: Neen.…”

Posted by jpluimers on 2020/08/12

[WayBackRoderick Gadellaa auf Twitter: “@ingnl Ik begrijp dat jullie gaan stoppen met TAN codes. Juich ik toe, 2FA met sms is behoorlijk lek. Maar nu moet ik jullie app gaan gebruiken. Ik werp 1 blik op de permissions die jullie app wil en denk: Neen.…”

Reminder to self: check what permissions are needed now.

–jeroen

Read the rest of this entry »

Posted in Development, Power User, Security, Software Development | Leave a Comment »

 
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