Autoruns 64 Vs Autoruns 64a __exclusive__

Autoruns 64 vs Autoruns 64a: Uncovering the Differences and Choosing the Right Tool for Your Needs

When it comes to managing startup programs and services on a Windows system, two popular tools often come to mind: Autoruns 64 and Autoruns 64a. Both are part of the Sysinternals suite, a collection of advanced system utilities developed by Mark Russinovich and acquired by Microsoft. While they share a similar name and purpose, there are key differences between Autoruns 64 and Autoruns 64a that can significantly impact their usability and effectiveness in different scenarios.

How to check your system architecture

• Win + R → msinfo32 → Look at System Type
  • x64-based PC → use Autoruns64
  • ARM-based PC → use Autoruns64a

Part 4: Do They Produce the Same Results?

This is the million-dollar question. For 99% of standard malware hunting and startup management, both autoruns64.exe and autoruns64a.exe produce identical output when run on the same machine. autoruns 64 vs autoruns 64a

However, there are edge cases:

1. Arm64 Native Auto-start Locations:
   Windows on ARM has introduced a few new ASEPs specific to ARM64 ecosystem components (e.g., certain type of scheduled tasks for ARM64-optimized background apps). An emulated x64 Autoruns might not enumerate these correctly because the COM object interfaces for those tasks may not be fully emulated. Autoruns 64 vs Autoruns 64a: Uncovering the Differences

2. ARM64 Kernel Drivers:
   Malware authors have begun writing native ARM64 rootkits for Windows on ARM. autoruns64a.exe has native access to query the ARM64 kernel driver list via the ZwQuerySystemInformation syscall. Under emulation, autoruns64.exe relies on thunking layers that could theoretically miss a driver that only registers itself with the ARM64 kernel subsystem.

3. Timing-Based Anti-Emulation Malware:
   Some sophisticated malware checks if it is running under emulation by measuring instruction execution latency (RDTSC/RDTSCP differences). If you run autoruns64.exe on ARM64, the emulation layer changes timing. Malware that detects emulation might hide its startup entries. autoruns64a.exe avoids this detection. Win + R → msinfo32 → Look at System Type

Verdict: For standard enterprise IT and most malware analysis, results are functionally identical. For incident response on ARM64 devices, always use autoruns64a.exe to be forensically sound.

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The Diverging Path: WOW64 vs. Native 64-bit

The "a" in autoruns64a stands for "AMD64" (or more broadly, x64 architecture). The version without the "a" is compiled for the Itanium (IA-64) architecture.

• Autoruns64 (without the "a"): This binary is compiled for Intel Itanium processors. In the early 2000s, Intel and HP developed the Itanium architecture (IA-64) as a high-performance 64-bit system for enterprise servers. However, Itanium failed in the consumer market. Today, Itanium is effectively obsolete. Unless you are maintaining a legacy Windows server from the mid-2000s (e.g., Windows Server 2008 for Itanium), this executable is useless.

• Autoruns64a (with the "a"): This is the version for x64 processors—the AMD64 standard used by virtually every modern desktop, laptop, and server CPU from both AMD and Intel. When users download the Autoruns package on a typical Windows 10 or Windows 11 PC, autoruns64a.exe is the correct file to run.