Identifier / Programs / Linux and Unix
nasm
The Netwide Assembler, a portable 80x86 assembler. tldr-pages
GTFOBins file-read 1 documented command
How nasm is abused
file-read
Each abuse is GTFOBins's category and the options and words it uses; the full write-up is on GTFOBins's page for nasm.
1 documented command
file-read unprivileged, with sudo, as SUID
The file content is treated as command line options and disclosed throught error messages.
nasm -@ /path/to/input-fileThe command the identifier reads trips no Sigma process-creation rule. This command is, with GTFOBins’ notes, from GTFOBins, at commit acd524623f9c of 2026-05-27, under the GPL-3.0, with no warranty. Changed: Markdown is shown formatted. The source is in lolbas-gtfobins-commands.json.gz, and the full entry is on GTFOBins’s page for nasm. The identifier reads the line that runs nasm.
Everyday use
Assemble source.asm into a binary file source, in the (default) raw binary format
nasm source.asmIdentifyAssemble source.asm into a binary file output_file, in the specified format
nasm -f format source.asm -o output_fileIdentifyList valid output formats (along with basic nasm help)
nasm -hfIdentifyNone of the 3 examples the identifier reads matches GTFOBins abuse or trips a Sigma process-creation rule.