Summary: Depends on D20024. See D20022. Put something in place temporarily until we build out validation at some point.
Test Plan: Sent myself a test message.
Reviewers: amckinley
Reviewed By: amckinley
Differential Revision: https://secure.phabricator.com/D20025
Summary:
Depends on D20018. Ref T13222. When you add a new MFA configuration, you can technically (?) guess your way through it with brute force. It's not clear why this would ever really be useful (if an attacker can get here and wants to add TOTP, they can just add TOTP!) but it's probably bad, so don't let users do it.
This limit is fairly generous because I don't think this actually part of any real attack, at least today with factors we're considering.
Test Plan:
- Added TOTP, guessed wrong a ton of times, got rate limited.
- Added TOTP, guessed right, got a TOTP factor configuration added to my account.
Reviewers: amckinley
Reviewed By: amckinley
Maniphest Tasks: T13222
Differential Revision: https://secure.phabricator.com/D20019
Summary:
Depends on D19897. Ref T13222. See some discussion in D19890.
- Only rate limit users if they're actually answering a challenge, not if they're just clicking "Wait Patiently".
- Reduce the number of allowed attempts per hour from 100 back to 10.
- Reduce the TOTP window from +/- 2 timesteps (allowing ~60 seconds of skew) to +/- 1 timestep (allowing ~30 seconds of skew).
- Change the window where a TOTP response remains valid to a flat 60 seconds instead of a calculation based on windows and timesteps.
Test Plan:
- Hit an MFA prompt.
- Without typing in any codes, mashed "submit" as much as I wanted (>>10 times / hour).
- Answered prompt correctly.
- Mashed "Wait Patiently" as much as I wanted (>>10 times / hour).
- Guessed random numbers, was rate limited after 10 attempts.
Reviewers: amckinley
Reviewed By: amckinley
Maniphest Tasks: T13222
Differential Revision: https://secure.phabricator.com/D19898
Summary:
Depends on D19889. Ref T13222. Some of this logic is either not-quite-right or a little more complicated than it needs to be.
Currently, we TTL TOTP challenges after three timesteps -- once the current code could no longer be used. But we actually have to TTL it after five timesteps -- once the most-future acceptable code could no longer be used. Otherwise, you can enter the most-future code now (perhaps the attacker compromises NTP and skews the server clock back by 75 seconds) and then an attacker can re-use it in three timesteps.
Generally, simplify things a bit and trust TTLs more. This also makes the "wait" dialog friendlier since we can give users an exact number of seconds.
The overall behavior here is still a little odd because we don't actually require you to respond to the challenge you were issued (right now, we check that the response is valid whenever you submit it, not that it's a valid response to the challenge we issued), but that will change in a future diff. This is just moving us generally in the right direction, and doesn't yet lock everything down properly.
Test Plan:
- Added a little snippet to the control caption to list all the valid codes to make this easier:
```
$key = new PhutilOpaqueEnvelope($config->getFactorSecret());
$valid = array();
foreach ($this->getAllowedTimesteps() as $step) {
$valid[] = self::getTOTPCode($key, $step);
}
$control->setCaption(
pht(
'Valid Codes: '.implode(', ', $valid)));
```
- Used the most-future code to sign `L3`.
- Verified that `L4` did not unlock until the code for `L3` left the activation window.
Reviewers: amckinley
Reviewed By: amckinley
Maniphest Tasks: T13222
Differential Revision: https://secure.phabricator.com/D19890
Summary:
Depends on D18904. Ref T13043. If an attacker compromises a victim's session and bypasses their MFA, they can try to guess the user's current account password by making repeated requests to change it: if they guess the right "Old Password", they get a different error than if they don't.
I don't think this is really a very serious concern (the attacker already got a session and MFA, if configured, somehow; many installs don't use passwords anyway) but we get occasional reports about it from HackerOne. Technically, it's better policy to rate limit it, and this should reduce the reports we receive.
Test Plan: Tried to change password over and over again, eventually got rated limited. Used `bin/auth unlimit` to clear the limit, changed password normally without issues.
Reviewers: amckinley
Reviewed By: amckinley
Maniphest Tasks: T13043
Differential Revision: https://secure.phabricator.com/D18906
Summary: Ref T4398. Prevent users from brute forcing multi-factor auth by rate limiting attempts. This slightly refines the rate limiting to allow callers to check for a rate limit without adding points, and gives users credit for successfully completing an auth workflow.
Test Plan: Tried to enter hisec with bad credentials 11 times in a row, got rate limited.
Reviewers: btrahan
Reviewed By: btrahan
Subscribers: epriestley
Maniphest Tasks: T4398
Differential Revision: https://secure.phabricator.com/D8911
