CVE-2017-11424
Published: 24 August 2017
In PyJWT 1.5.0 and below the `invalid_strings` check in `HMACAlgorithm.prepare_key` does not account for all PEM encoded public keys. Specifically, the PKCS1 PEM encoded format would be allowed because it is prefaced with the string `-----BEGIN RSA PUBLIC KEY-----` which is not accounted for. This enables symmetric/asymmetric key confusion attacks against users using the PKCS1 PEM encoded public keys, which would allow an attacker to craft JWTs from scratch.
Notes
| Author | Note |
|---|---|
| tyhicks | The added deprecation warnings present in the fix probably aren't needed in security backports |
Priority
Status
| Package | Release | Status |
|---|---|---|
|
pyjwt Launchpad, Ubuntu, Debian |
trusty |
Does not exist
|
| upstream |
Needed
|
|
| xenial |
Released
(1.3.0-1ubuntu0.1)
|
|
| zesty |
Released
(1.4.2-1ubuntu0.1)
|
|
|
Patches: upstream: https://github.com/jpadilla/pyjwt/pull/277 |
||
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 7.5 |
| Attack vector | Network |
| Attack complexity | Low |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | None |
| Integrity impact | High |
| Availability impact | None |
| Vector | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |