Exploitalert - Database of Exploits

Microsoft Windows 7 Group Policy Privilege Escalation

CVE	Category	Price	Severity
CVE-2016-3223	CWE-264	$50,000	High

Author	Risk	Exploitation Type	Date
Unknown	High	Local	2016-08-10

CPE
cpe:cpe:/o:microsoft:windows:7

CVSS	EPSS	EPSSP
CVSS:4.0/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H	0.34948	0.78156

CVSS vector description

Metric	Value	Metric Description	Value Description
Attack vector	Network	AV	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	High	PR	The attacker requires privileges that provide significant (e.g., administrative) control over the vulnerable system allowing full access to the vulnerable system’s settings and files.
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.

https://cxsecurity.com/ascii/WLB-2016080098

Microsoft Windows 7 Group Policy Privilege Escalation# Exploit Title: Group Policy Elevation of Privilege Vulnerability # Date: 08-08-2016 # Exploit Author: Nabeel Ahmed # Tested on: Windows 7 Professional (x32/x64) # CVE : CVE-2016-3223 # Category: Privilege Escalation SPECIAL CONFIG: Standard Domain Member configuration with valid credentials. (Standard Domain User with valid credentials) SUMMARY: This vulnerability allows an attacker to create/modify local Administrator account through a fake Domain Controller by creating User Configuration Group Policies. 1) Prerequisites: - Standard Windows 7 Fully patched and member of an existing domain. (e.g. domain.local) - Domain User Credentials are known with no Administrative rights. - Computer has to be connected on a network. - Fake Domain Controller 2) Reproduce: STEP 1: Determine domain of the target computer (e.g. domain.local) STEP 2: Boot system and determine FQDN of the device. (example. CLIENT.domain.local), this can be obtained by monitoring the network broadcast communication, which the system sends prior to loggin in. The username can be extracted from the loginscreen (E.g USER1) STEP 3: Create Active Directory for the domain you obtained in STEP 2 (domain.local). STEP 4: Create User with similar name and password as the target computer. (E.g. domainUSER1:password123!). STEP 5: Login on the target system with the known Username and Password without any network connection (using cached credentials). STEP 6: Establish network connection between the target system and the newly created Domain Controller. STEP 7: Create a Group Policy called "Create Local Admin" STEP 8: Edit the "Create Local Admin" Group Policy to create in the User Configuration section a new user called "TestAdmin" and add him to the group "Administrators". STEP 9: Open Command Prompt on the target system and execute the following command: "gpupdate /target:user /force" STEP 10: User Policy update will complete successfully. STEP 11: Confirm the newly created Administrator "TestAdmin" by executing the following command in Command Prompt: "net localgroup Administrators" STEP 12: "TestAdmin" user will be member of the Administrators group. 3) Impact: A regular Domain User can gain higher privileges on his system by creating a new administrator through Group Policies created on a fake Domain Controller 4) Solution: Install the latest patches from 14-06-2016 using Windows Update. 5) References: https://technet.microsoft.com/en-us/library/security/ms16-072.aspx https://support.microsoft.com/en-us/kb/3163622 6) Credits: Vulnerability discovered by Nabeel Ahmed (https://twitter.com/NabeelAhmedBE) and Tom Gilis (https://twitter.com/tgilis) of Dimension Data (https://www.dimensiondata.com)

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