Valid Accounts: Default Accounts Defense Evasion [Mitre]

Adversaries may obtain and abuse credentials of a default account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Default accounts are those that are built-into an OS, such as the Guest or Administrator accounts on Windows systems. Default accounts also include default factory/provider set accounts on other types of systems, software, or devices, including the …

Default Windows Wallpaper Check Sandbox Evasion

Adversaries may employ various user activity checks to detect and avoid virtualization and analysis environments. This may include changing behaviors based on the results of checks for the presence of artifacts indicative of a virtual machine environment (VME) or sandbox. In this particular case, the malware checks to see if the wallpaper set on the machine is the default Windows …

Connected Printer Sandbox Evasion

Another technique for detecting if a program is running in a sandbox is to look for potential connected printers or identify the default Windows printers, Adobe, or OneNote. This is because sandboxes typically do not have access to printers, and detecting the absence of printers can help identify whether the program is being run in a sandbox environment.

Indicator Removal: Clear Network Connection History and Configurations Defense Evasion [Mitre]

Adversaries may clear or remove evidence of malicious network connections in order to clean up traces of their operations. Configuration settings as well as various artifacts that highlight connection history may be created on a system from behaviors that require network connections, such as Remote Services or External Remote Services. Defenders may use these artifacts to monitor or otherwise analyze …

CsrGetProcessID Anti-Debugging

This function is undocumented within OpenProcess. It can be used to get the PID of CRSS.exe, which is a SYSTEM process. By default, a process has the SeDebugPrivilege privilege in their access token disabled.

However, when the process is loaded by a debugger such as OllyDbg or WinDbg, the SeDebugPrivilege privilege is enabled. If a process is able …

NtGlobalFlag Anti-Debugging

The information that the system uses to determine how to create heap structures is stored at an undocumented location in the PEB at offset 0x68. If the value at this location is 0x70, we know that we are running in a debugger.

The NtGlobalFlag field of the Process Environment Block (0x68 offset on 32-Bit and 0xBC on …

Call Trick Anti-Disassembly

The call trick is an anti-disassembling technique that involves modifying the default function's return address. This can be used in conjunction with other techniques, such as the insertion of garbage bytes, to break disassemblers. Disassemblers that use recursive traversal or linear sweep may be particularly vulnerable to this trick, as they may be unable to accurately interpret the next instruction …

Breaking BaDDEr Process Manipulating

Dynamic Data Exchange (DDE) is a protocol that allows applications to share data with each other. The Dynamic Data Exchange Management Library (DDEML) is a set of functions that facilitate data sharing using the DDE protocol. DDE and DDEML are commonly used in Microsoft Office to enable data to be shared between applications. In October 2017, a vulnerability was discovered …

Detecting Online Sandbox Sandbox Evasion

Online sandbox has become very popular for malware analysis. Several malware authors employ such techniques to avoid detection and analysis. Some of these techniques will be summarized here.

Any.Run uses a fake root certificate to spy on sandbox traffic. The first information about the system can be obtained by querying the information of the root certificate. In …

BobSoft Mini Delphi Packer Packers

The Delphi programming language can be an easy way to write applications and programs that leverage Windows API functions. In fact, some actors deliberately include the default libraries as a diversion to hamper static analysis and make the application "look legit" during dynamic analysis.

The packer goes to great lengths to ensure that it is not running in an …

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