Identifier / Programs / Linux and Unix

chmod

Change the access permissions of a file or directory. tldr-pages

GTFOBins privilege-escalation 2 Sigma rules name it 1 ATT&CK technique 1 documented command

How chmod is abused

documented by GTFOBins

privilege-escalation

Each abuse is GTFOBins's category and the options and words it uses; the full write-up is on GTFOBins's page for chmod.

1 documented command

from GTFOBins, each read by the identifier

privilege-escalation with sudo, as SUID

This can be run with elevated privileges to change permissions (6 denotes the SUID bits) and then read, write, or execute a file.

chmod 6777 /path/to/input-file

Identify

The 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 chmod. The identifier reads the line that runs chmod.

What detects it

Sigma process creation rules

mediumChmod Targeting Sensitive DirectoriesChristopher Peacock @SecurePeacock, SCYTHE @scythe_io

mediumSuspicious Execution via macOS Script EditorTim Rauch (rule), Elastic (idea)

T1222.002File and Directory Permissions Modification: Linux and Mac Permissions

Everyday use

from tldr-pages, CC BY 4.0

Give the user who owns a file the right to execute it

chmod u+x path/to/fileIdentify

Give the user rights to read and write to a file/directory

chmod u+rw path/to/file_or_directoryIdentify

Remove executable rights from the group and others

chmod g-x,o-x path/to/fileIdentify

None of the 3 examples the identifier reads matches GTFOBins abuse or trips a Sigma process-creation rule.

Options

4 in toybox

Show every option of chmod

-cPrint changes

-fDon't print errors

-RRecursive

-vVerbose