XProtect Encryption Abuse Data Obfuscation

Malware can abuse Apple's macOS XProtect string encryption algorithm to hide critical strings, including commands, browser paths, extension IDs, cryptocurrency wallet locations, and command-and-control (C2) details.

This technique leverages the same XOR-based encryption logic implemented in macOS’s XProtect antivirus engine, this encryption is used for “encrypted YARA rules stored within the XProtect Remediator binaries”.

The encryption process involves …

Clearing Kernel Message Anti-Forensic

The dmesg -C command clears the kernel message buffer, which stores diagnostic messages generated by the kernel. These messages include logs about hardware interactions, system events, kernel module loads, and errors such as segmentation faults. The attacker can run this command to make sure that no trace of kernel-related activity, including any anomalies caused by exploitation, remains in the message …

Manipulating Debug Logs Anti-Forensic

Using the sed -i command, specific entries in debug logs, such as errors (segfault, SystemError) or trace information (e.g., filenames like main.cc), are surgically removed. This allows attackers to target only incriminating evidence without erasing the entire log file. The process preserves the structure and authenticity of the log while removing key evidence of exploitation or system errors.

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Deleting Troubleshoot Information and Core Dumps Anti-Forensic

Commands like rm -rf /data/var/statedumps/* and rm -rf /data/var/cores/* delete state dumps and core dumps, which are generated when processes crash. These files contain memory snapshots, stack traces, and runtime states of processes at the time of failure. They are often used to debug and understand the causes of crashes or application malfunctions.

Attackers use this technique to eliminate …

Detecting Mac Address Sandbox Evasion

Virtualbox and VMware use specific virtual Mac address that can be detected by Malware.

The usual mac address used by Virtualbox starts with the following number: 08:00:27.
The usual mac address used by VMware starts with the following numbers: 00:0C:29, 00:1C:14, 00:50:56, 00:05:69.

Malware can use this simple trick to detect if it is running …

Detecting Virtual Environment Process Sandbox Evasion

Process related to Virtualbox can be detected by malware by query the process list.

The VMware Tools use processes like VMwareServices.exe or VMwareTray.exe, to perform actions on the virtual environment. A malware can list the process and searches for the VMware string. Process: VMwareService.exe, VMwareTray.exe, TPAutoConnSvc.exe, VMtoolsd.exe, VMwareuser.exe.

Detecting Virtual Environment Files Sandbox Evasion

Some files are created by Virtualbox and VMware on the system.

Malware can check the different folders to find Virtualbox artifacts like VBoxMouse.sys.

Malware can check the different folders to find VMware artifacts like vmmouse.sys, vmhgfs.sys.

Some Files Example

Below is a list of files that can be detected on virtual machines:

"C:\ProgramData\Microsoft\Windows\Start Menu\Programs\StartUp\agent.pyw",

SLDT, No Pill Sandbox Evasion

The No Pill technique is a method used by malware to determine whether it is running on a physical machine or a virtual machine. This technique relies on the fact that the Local Descriptor Table (LDT) is assigned to a processor, rather than to an operating system. On a physical machine, the location of the LDT will be zero, whereas …

SMSW Sandbox Evasion

Stores the machine status word into the destination operand.

STR Sandbox Evasion

Stores the segment selector from the Task Register (TR).

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