60%
68%
106%
Microsoft Windows 7 SP1, Windows Server 2008 SP2 and R2 SP1, Windows 8.1 and Windows RT 8.1, Windows Server 2012 and R2, Windows 10 Gold, 1511, 1607, and 1703, and Windows Server 2016 allows an attacker to bypass Extended Protection for Authentication when Kerberos fails to prevent tampering with the SNAME field during ticket exchange, aka "Kerberos SNAME Security Feature Bypass Vulnerability" or Orpheus' Lyre.
Microsoft Windows 7 SP1, Windows Server 2008 SP2 and R2 SP1, Windows 8.1 and Windows RT 8.1, Windows Server 2012 and R2, Windows 10 Gold, 1511, 1607, and 1703, and Windows Server 2016 allows an attacker to bypass Extended Protection for Authentication when Kerberos fails to prevent tampering with the SNAME field during ticket exchange, aka "Kerberos SNAME Security Feature Bypass Vulnerability" or Orpheus' Lyre.
CVSS 3.0 Base Score 7.5. CVSS Attack Vector: network. CVSS Attack Complexity: high. CVSS Vector: (CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H).
CVSS 2.0 Base Score 6. CVSS Attack Vector: network. CVSS Attack Complexity: medium. CVSS Vector: (AV:N/AC:M/Au:S/C:P/I:P/A:P).
The following code intends to ensure that the user is already logged in. If not, the code performs authentication with the user-provided username and password. If successful, it sets the loggedin and user cookies to "remember" that the user has already logged in. Finally, the code performs administrator tasks if the logged-in user has the "Administrator" username, as recorded in the user cookie.
}
}ExitError("Error: you need to log in first");
););DoAdministratorTasks();Unfortunately, this code can be bypassed. The attacker can set the cookies independently so that the code does not check the username and password. The attacker could do this with an HTTP request containing headers such as:
[body of request]By setting the loggedin cookie to "true", the attacker bypasses the entire authentication check. By using the "Administrator" value in the user cookie, the attacker also gains privileges to administer the software.
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