unveilingsedexp-reichert2024

2025-04-03

Unveiling “sedexp”: A Stealthy Linux Malware Exploiting udev Rules

by Zachary Reichert

August 19. 2024

https://www.aon.com/en/insights/cyber-labs/unveiling-sedexp

Notes
Stroz Friedberg
malware
Linux malware
Linux
sedexp
udev
udev rules
persistence
evasion
reverse shell
MITRE ATT&CK
udev persistence was not documented in ATT&CK
financially motivated threat actor
/dev
Linux kernel
device node
hotplug
USB
etc/udev/rules.d
lib/udev/rules.d
udev rule format: ACTION, ENV{MAJOR}, ENV{MINOR}, RUN
/dev/random
memory modification for stealth
webshell
Apache
changes process name to kdevtmpfs using prctl
prctl
blend in with legitimate processes
readlink()
/proc/self/exe
threat intelligence
credit card scraping
OSINT
online sandboxes had zero detections
been in use since at least 2022
DFIR
Samples
43f72f4cdab8ed40b2f913be4a55b17e7fd8a7946a636adb4452f685c1ffea02
94ef35124a5ce923818d01b2d47b872abd5840c4f4f2178f50f918855e0e5ca2
b981948d51e344972d920722385f2370caf1e4fac0781d508bc1f088f477b648

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