68%
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A vulnerability in the boot logic of Cisco IOS XE Software could allow an authenticated, local attacker with level 15 privileges or an unauthenticated attacker with physical access to execute arbitrary code on the underlying Linux operating system of an affected device. This vulnerability is due to incorrect validations of specific function arguments that are passed to the boot script. An attacker could exploit this vulnerability by tampering with a specific file, which an affected device would process during the initial boot process. On systems that are protected by the Unified Extensible Firmware Interface (UEFI) secure boot feature, a successful exploit could allow the attacker to execute unsigned code at boot time and bypass the image verification check in the secure boot process of the affected device.
CVSS 3.1 Base Score 6.8. CVSS Attack Vector: physical. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
CVSS 2.0 Base Score 6.9. CVSS Attack Vector: local. CVSS Attack Complexity: medium. CVSS Vector: (AV:L/AC:M/Au:N/C:C/I:C/A:C).
Debug code can be used to bypass authentication. For example, suppose an application has a login script that receives a username and a password. Assume also that a third, optional, parameter, called "debug", is interpreted by the script as requesting a switch to debug mode, and that when this parameter is given the username and password are not checked. In such a case, it is very simple to bypass the authentication process if the special behavior of the application regarding the debug parameter is known. In a case where the form is:
</FORM><INPUT TYPE=SUBMIT>Then a conforming link will look like:
http://TARGET/authenticate_login.cgi?username=...&password=...An attacker can change this to:
http://TARGET/authenticate_login.cgi?username=&password=&debug=1Which will grant the attacker access to the site, bypassing the authentication process.
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