CVE-2015-2823 - Improper Authentication

Severity

68%

Complexity

86%

Confidentiality

106%

Siemens SIMATIC HMI Basic Panels 2nd Generation before WinCC (TIA Portal) 13 SP1 Upd2, SIMATIC HMI Comfort Panels before WinCC (TIA Portal) 13 SP1 Upd2, SIMATIC WinCC Runtime Advanced before WinCC (TIA Portal) 13 SP1 Upd2, SIMATIC WinCC Runtime Professional before WinCC (TIA Portal) 13 SP1 Upd2, SIMATIC HMI Basic Panels 1st Generation (WinCC TIA Portal), SIMATIC HMI Mobile Panel 277 (WinCC TIA Portal), SIMATIC HMI Multi Panels (WinCC TIA Portal), and SIMATIC WinCC 7.x before 7.3 Upd4 allow remote attackers to complete authentication by leveraging knowledge of a password hash without knowledge of the associated password.

Siemens SIMATIC HMI Basic Panels 2nd Generation before WinCC (TIA Portal) 13 SP1 Upd2, SIMATIC HMI Comfort Panels before WinCC (TIA Portal) 13 SP1 Upd2, SIMATIC WinCC Runtime Advanced before WinCC (TIA Portal) 13 SP1 Upd2, SIMATIC WinCC Runtime Professional before WinCC (TIA Portal) 13 SP1 Upd2, SIMATIC HMI Basic Panels 1st Generation (WinCC TIA Portal), SIMATIC HMI Mobile Panel 277 (WinCC TIA Portal), SIMATIC HMI Multi Panels (WinCC TIA Portal), and SIMATIC WinCC 7.x before 7.3 Upd4 allow remote attackers to complete authentication by leveraging knowledge of a password hash without knowledge of the associated password.

CVSS 2.0 Base Score 6.8. CVSS Attack Vector: network. CVSS Attack Complexity: medium. CVSS Vector: (AV:N/AC:M/Au:N/C:P/I:P/A:P).

Demo Examples

Improper Authentication

CWE-287

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.

Improper Authentication

CWE-287

Overview

Type

Siemens WinCC

First reported 10 years ago

2015-04-08 16:59:00

Last updated 8 years ago

2016-11-28 19:21:00

Affected Software

Siemens WinCC 7.0

7.0

Siemens WinCC 7.1

7.1

Siemens WinCC 7.2

7.2

Siemens WinCC 7.3

7.3

References

74040

http://www.siemens.com/innovation/pool/de/forschungsfelder/siemens_security_advisory_ssa-487246.pdf

Patch, Vendor Advisory

https://cert-portal.siemens.com/productcert/pdf/ssa-487246.pdf

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