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Adversaries may use binary padding to add junk data and change the on-disk representation of malware.
Passed 20 of 22 test cases with the skill, and 14 of 22 without it.
and 4 more in the full report
6 fixed14 passed either way2 still failing0 broke
Tokens, turns and time describe resource use, not a dollar price.
One of 6 test cases the skill fixed. Same model, same prompt, with and without the skill.
An analyst attempts to emulate T1027.001 on macOS using `truncate -s 10M /tmp/evil-binary` to set the file size to 10MB. What specific `truncate` size flag syntax is used in Atomic Test 2 to increment the file size rather than set a fixed total size?
| Checked | Without skill | With skill |
|---|---|---|
| The size argument uses `+1` to add a byte. | Missed | Passed |
The instructions your model reads when the skill loads.
Sub-technique of: T1027
Adversaries may use binary padding to add junk data and change the on-disk representation of malware. This can be done without affecting the functionality or behavior of a binary, but can increase the size of the binary beyond what some security tools are capable of handling due to file size limitations.
Binary padding effectively changes the checksum of the file and can also be used to avoid hash-based blocklists and static anti-virus signatures. The padding used is commonly generated by a function to create junk data and then appended to the end or applied to sections of malware. Increasing the file size may decrease the effectiveness of certain tools and detection capabilities that are not designed or configured to scan large files. This may also reduce the likelihood of being collected for analysis. Public file scanning services, such as VirusTotal, limits the maximum size of an uploaded file to be analyzed.
Platforms: Linux, Windows, macOS
The following tests are from Atomic Red Team and provide actionable ways to test this technique:
Uses dd to add a zero byte, high-quality random data, and low-quality random data to the binary to change the hash.
Upon successful execution, dd will modify /tmp/evil-binary, therefore the expected hash will change.
Supported Platforms: linux, macos
dd if=/dev/zero bs=1 count=1 >> #{file_to_pad} #adds null bytes
test cases passed, vs 14 / 22 without
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