Adversaries may employ various means to detect and avoid debuggers. Debuggers are typically used by defenders to trace and/or analyze the execution of potential malware payloads.(Citation: ProcessHacker Github)
Debugger evasion may include changing behaviors based on the results of the checks for the presence of artifacts indicative of a debugged environment. Similar to Virtualization/Sandbox Evasion, if the adversary detects a debugger, they may alter their malware to disengage from the victim or conceal the core functions of the implant. They may also search for debugger artifacts before dropping secondary or additional payloads.
Specific checks will vary based on the target and/or adversary, but may involve Native API function calls such as <code>IsDebuggerPresent()</code> and <code> NtQueryInformationProcess()</code>, or manually checking the <code>BeingDebugged</code> flag of the Process Environment Block (PEB). Other checks for debugging artifacts may also seek to enumerate hardware breakpoints, interrupt assembly opcodes, time checks, or measurements if exceptions are raised in the current process (assuming a present debugger would “swallow” or handle the potential error).(Citation: hasherezade debug)(Citation: AlKhaser Debug)(Citation: vxunderground debug)
Adversaries may use the information learned from these debugger checks during automated discovery to shape follow-on behaviors. Debuggers can also be evaded by detaching the process or flooding debug logs with meaningless data via messages produced by looping Native API function calls such as <code>OutputDebugStringW()</code>.(Citation: wardle evilquest partii)(Citation: Checkpoint Dridex Jan 2021)
View in MITRE ATT&CK®| Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name | Notes |
|---|---|---|---|---|---|
| CVE-2015-3113 | Adobe Flash Player Heap-Based Buffer Overflow Vulnerability | secondary_impact | T1622 | Debugger Evasion |
Comments
This heap-based buffer overflow vulnerability is exploited by having a user open a maliciously-crafted file.
In the wild, this exploitation has been used in order to establish command and control (over HTTP) with a target system. The command and control functionality has also been seen to employ debugging/sandboxing evasion.
References
|
| CVE-2022-42475 | Fortinet FortiOS Heap-Based Buffer Overflow Vulnerability | secondary_impact | T1622 | Debugger Evasion |
Comments
CVE-2022-42475 is a remotely-expoitable heap overflow vulnerability. Adversaries have been observed exploiting this vulnerability to deliver malicious software to the target device.
This malicious software has observed anti-debugging and command and control capabilities (over HTTP).
References
|