Temporary Files (%temp%)

Purpose and Function

The Temporary Files folder, commonly accessed via the %temp% environment variable, is a designated directory used by the Windows operating system and various applications to store transient data. Its primary purpose is to hold files that are needed for a short period during an application's operation, installation, or a specific system task. This can include cache files, temporary copies of documents being edited, installation logs, or files extracted from compressed archives.

From a DFIR perspective, the %temp% folder is a crucial location to search for artifacts related to recent user activity. Because it is a common, user-writable location, it is frequently used by legitimate and malicious software alike as a scratchpad, often leaving behind valuable evidence.

Location and Structure

Each user on a Windows system has their own temporary folder, ensuring that an application's temporary data is isolated to the user running it.

• Location: %LOCALAPPDATA%\Temp

  • This typically resolves to: C:\Users\%username%\AppData\Local\Temp

The folder itself is a standard directory containing a mix of files and subdirectories created by numerous different processes. The contents can be vast and often appear chaotic, requiring a targeted approach to analysis, usually by sorting by "Date Modified" to focus on the most recent items.

Stored Artifacts and Forensic Value

While the contents of the %temp% folder are diverse, several specific types of artifacts are of high forensic value, particularly in the context of cheat detection.

• Extracted Archives: When a user runs an executable directly from within a compressed archive (like a .zip, .rar, or .7z file) without fully extracting it first, the archiving tool (e.g., WinRAR, 7-Zip) often temporarily extracts the necessary files to a newly created subdirectory within %temp%. These temporary folders may have names like Rar$EXa0.123 or 7zOADF8.tmp. Examining the contents and modification timestamps of these temporary folders can reveal recently executed programs that were run from archives.

• JnativeHook Libraries: Certain Java-based applications, particularly some autoclickers and macro tools, utilize a third-party library called JnativeHook to interact with global keyboard and mouse inputs. When these applications are executed, they often drop a native library file (a DLL) into the %temp% directory. This file typically follows the naming pattern JnativeHook-xxxxxxxx.dll. The creation timestamp of this DLL file directly corresponds to the time the parent Java application was executed.

• Application Logs and Caches: Many applications store temporary logs, configuration data, or cached files in this directory. Analyzing these can provide context about the application's recent activity or settings.

• Malware Dropper Remnants: Malware or cheat loaders sometimes use the %temp% folder as a staging area to drop secondary payloads or scripts before executing them.

The primary challenge in analyzing the %temp% folder is its volatility and the sheer volume of "noise" from legitimate applications. However, its contents are directly attributable to the user, and the timestamps of files within it can provide high-precision evidence of recent activity.

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Reflection points (SS Contest)

For a ScreenSharer, the %temp% folder is a high-priority location for finding evidence of recently used tools, especially those that don't install themselves permanently.

• The JnativeHook "Smoking Gun": The presence of a JnativeHook-xxxxxxxx.dll file is one of the most well-known and direct indicators of a Java-based autoclicker. An SSer can sort the %temp% folder by date and immediately spot this file. Its creation time provides the exact moment the cheat was launched. Even if the file is deleted, the deletion event can be found in the USN Journal.

• Unmasking Cheats Run from ZIPs: This is a very common scenario. A player downloads a cheat in a .zip file and, to avoid leaving it on their desktop, runs it directly from the archive. An SSer can find the temporary extraction folder in %temp%, which will contain the cheat executable itself. The folder's creation/modification time will pinpoint the time of execution.

• A First Look at Recent Activity: Simply opening %temp% and sorting by "Date Modified" is one of the quickest ways to get a sense of what a player was doing right before the screenshare. Newly created folders or suspicious file types (.exe, .dll, .jar) that appear at the top of the list are immediate targets for investigation.

• Finding Dropped Files: If a cheat loader was executed, it might have dropped its payload (the actual cheat) into %temp%. Finding an unsigned executable with a very recent creation time in this folder is highly suspicious.