Add mitigation against BREACH #18254
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| @@ -1057,7 +1057,7 @@ public static function getInstanceId() { | |||
| /** | |||
| * Register an get/post call. Important to prevent CSRF attacks. | |||
| * | |||
| * @return string Generated token. | |||
| * @return string XOR'd CSRF token with an appended random separated by `:` | |||
LukasReschke
force-pushed
the
mitigate-breach
branch
from
d17ed9d to
e51d717
Compare
sigh |
| @@ -415,8 +421,25 @@ public function passesCSRFCheck() { | |||
| return false; | |||
| } | |||
|
|
|||
| if(is_null($this->crypto)) { | |||
There was a problem hiding this comment.
Fixed. Needed some small change to base.php though since autoloading is not available at this stuff and cyclic dependency fun…
LukasReschke
force-pushed
the
mitigate-breach
branch
from
e51d717 to
89b78bc
Compare
While BREACH requires the following three factors to be effectively exploitable we should add another mitigation: 1. Application must support HTTP compression 2. Response most reflect user-controlled input 3. Response should contain sensitive data Especially part 2 is with ownCloud not really given since user-input is usually only echoed if a CSRF token has been passed. To reduce the risk even further it is however sensible to encrypt the CSRF token with a shared secret. Since this will change on every request an attack such as BREACH is not feasible anymore against the CSRF token at least.
LukasReschke
force-pushed
the
mitigate-breach
branch
from
89b78bc to
df2ce8a
Compare
|
A new inspection was created. |
|
Let's try again before creating a new branch. |
|
🚀 Test PASSed.🚀 |
|
Reviews? 🙊 To test this basically take a look at the HTML source of ownCloud and check if the requesttoken is different each reload. Besides that click around and check if there are no CSRF token fails ;) |
|
This wants reviewers lalalalalala – just 👍'ing is also fine 🙊 |
|
looks good 👍 |
|
Did some tests - works 👍 |
MorrisJobke
added a commit
that referenced
this pull request
Aug 24, 2015
Add mitigation against BREACH
Sign up for free
to subscribe to this conversation on GitHub.
Already have an account?
Sign in.
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
While BREACH requires the following three factors to be effectively exploitable we should add another mitigation:
Especially part 2 is with ownCloud not really given since user-input is usually only echoed if a CSRF token has been passed. (though there are parts such as the search box…)
To reduce the risk even further it is however sensible to encrypt the CSRF token with a shared secret. Since this will change on every request an attack such as BREACH is not feasible anymore against the CSRF token at least.
cc @owncloud/security-team Care to review?