SRC-2016-0000 : ATutor LMS Password Hash Usage Authentication Bypass Vulnerability



CVSS Score:

6.8, (AV:N/AC:M/Au:N/C:C/I:C/A:C)

Affected Vendors:


Affected Products:

ATutor 2.2.1 is confirmed, other versions may also be affected.

Vulnerability Details:

This vulnerability allows remote attackers to bypass authentication on vulnerable installations of ATutor. User interaction is not required to exploit this vulnerability.

The specific flaw exists within the handling of challenges for authentication. The implementation of the challenge allows an attacker to authenticate to the system if they have possession of the password hash but not the password for a user. An attacker can leverage this vulnerability in conjunction with other vulnerabilities to bypass authentication.

Vendor Response:

ATutor has not issued an update to correct this vulnerability.

Disclosure Timeline:

  • 2016-02-23 – Vulnerability reported to vendor
  • 2016-03-06 – Uncoordinated public release of advisory

Proof of Concept:



This vulnerability was discovered by Steven Seeley of Source Incite