Identifier / Programs / Linux and Unix
c89
GTFOBins file-read, file-write, shell 1 Sigma rule name it 1 ATT&CK technique 4 documented commands
How c89 is abused
file-read
-x-Efile-write
-x-oshell T1059.004 Command and Scripting Interpreter: Unix Shell
-wrapperEach abuse is GTFOBins's category and the options and words it uses; the full write-up is on GTFOBins's page for c89.
4 documented commands
GTFOBins documents c89 with the commands of gcc.
file-read unprivileged, with sudo
gcc -x c -E /path/to/input-fileTrips no Sigma process-creation rule.
file-read unprivileged, with sudo
The file is read and parsed as a list of files (one per line), the content is displayed as error messages.
gcc @/path/to/input-fileTrips no Sigma process-creation rule.
file-write unprivileged, with sudo
This actually deletes the file.
gcc -x c /dev/null -o /path/to/input-fileTrips no Sigma process-creation rule.
shell unprivileged, with sudo
In some older versions, the x argument must instead reference any existing file.
gcc -wrapper /bin/sh,-s xTrips 1 Sigma rule: highShell Execution GCC - Linux by Li Ling, Andy Parkidomo, Robert Rakowski, Blake Hartstein (Bloomberg L.P.)
1 of the 4 commands the identifier reads trips a Sigma process-creation rule; 3 trip none. These commands are, 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 c89. The identifier reads the line of each that runs gcc.