PT-2021-14382 · Polr · Polr
Published
2021-02-01
·
Updated
2023-04-06
·
CVE-2021-21276
CVSS v3.1
9.3
Critical
| Vector | AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N |
Name of the Vulnerable Software and Affected Versions:
Polr versions prior to 2.3.0
Description:
Polr is an open source URL shortener. A vulnerability in the setup process allows attackers to gain admin access to site instances, even if they do not possess an existing account. This vulnerability exists regardless of users' settings. If an attacker crafts a request with specific cookie headers to the "/setup/finish" endpoint, they may be able to obtain admin privileges on the instance. This is caused by a loose comparison (==) in SetupController that is susceptible to attack. The project has been patched to ensure that a strict comparison (===) is used to verify the setup key, and that "/setup/finish" verifies that no users table exists before performing any migrations or provisioning any new accounts.
Recommendations:
For versions prior to 2.3.0, update to version 2.3.0 to fix the vulnerability.
As a temporary workaround, users can patch this vulnerability without upgrading by adding abort(404) to the very first line of finishSetup in SetupController.php.
Exploit
Fix
Incorrect Authorization
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Weakness Enumeration
Related Identifiers
Affected Products
Polr