NtGlobalFlag

Created the Monday 18 March 2019. Updated 1 year, 2 months ago.

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 64-bit Windows) is 0 by default. Attaching a debugger doesn’t change the value of NtGlobalFlag. However, if the process was created by a debugger, the following flags will be set:

  • FLG_HEAP_ENABLE_TAIL_CHECK (0x10)
  • FLG_HEAP_ENABLE_FREE_CHECK (0x20)
  • FLG_HEAP_VALIDATE_PARAMETERS (0x40)

The presence of a debugger can be detected by checking a combination of those flags.


Technique Identifiers

U0111 B0001.036

Technique Tag

ntglobalflag


Featured Windows API's

Below, you will find a list of the most commonly used Windows API's that are currently utilized by malware authors for current evasion technique. This list is meant to provide an overview of the API's that are commonly used for this purpose. If there are any API's that you feel should be included on this list, please do not hesitate to contact us. We will be happy to update the list and provide any additional information or documentation that may be helpful.

Code Snippets

Detection Rules

Additional Resources

External Links

The resources provided below are associated links that will give you even more detailed information and research on current evasion technique. It is important to note that, while these resources may be helpful, it is important to exercise caution when following external links. As always, be careful when clicking on links from unknown sources, as they may lead to malicious content.

Matching Samples 10 most recent

Sample Name Matching Techniques First Seen Last Seen
al-khaser.exe 24 2024-11-13 2 weeks, 6 days ago
View All

Sleeping Alien

Subscribe to our Newsletter

Don't miss out on the latest and greatest updates from us! Subscribe to our newsletter and be the first to know about exciting content and future updates.