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[FN Tuning] Shared Object Created or Changed by Previously Unknown Pr… #4529

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Merged
Aegrah merged 7 commits into from
Apr 8, 2025
Merged

[FN Tuning] Shared Object Created or Changed by Previously Unknown Pr… #4529

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[FN Tuning] Shared Object Created or Changed by Previously Unknown Pr…
Aegrah Mar 11, 2025
c339315
Merge branch 'main' into rule-tuning-shared-object-creation
DefSecSentinel Mar 14, 2025
5711659
Merge branch 'main' into rule-tuning-shared-object-creation
shashank-elastic Mar 14, 2025
e88bfce
Merge branch 'main' into rule-tuning-shared-object-creation
terrancedejesus Mar 15, 2025
d8bd5cf
Merge branch 'main' into rule-tuning-shared-object-creation
eric-forte-elastic Apr 3, 2025
3ed5856
Update process exclusions in TOML file
Aegrah Apr 8, 2025
5f00fc8
Merge branch 'main' into rule-tuning-shared-object-creation
Aegrah Apr 8, 2025
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17 changes: 10 additions & 7 deletions rules/linux/persistence_shared_object_creation.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@
creation_date = "2023/06/09"
integration = ["endpoint"]
maturity = "production"
updated_date = "2025/02/03"
updated_date = "2025/03/11"

[transform]
[[transform.osquery]]
Expand Down Expand Up @@ -160,17 +160,20 @@ tags = [
]
timestamp_override = "event.ingested"
type = "new_terms"

query = '''
host.os.type:linux and event.action:(creation or file_create_event or file_rename_event or rename) and
file.path:(/dev/shm/* or /usr/lib/*) and file.extension:so and process.name:* and not (
host.os.type:"linux" and event.action:("creation" or "file_create_event" or "file_rename_event" or "rename" or "file_write_event") and
(file.extension:"so" or file.name:*.so.*) and
file.path:(
/dev/shm/* or /usr/lib/* or /usr/lib64/* or /usr/local/lib/* or /usr/local/lib64/* or /lib/x86_64-linux-gnu/* or
/usr/lib/x86_64-linux-gnu/* or /lib/i386-linux-gnu/* or /usr/lib/i386-linux-gnu/* or /lib/* or /lib64/*
) and not (
process.name:(
"dockerd" or "dpkg" or "rpm" or "snapd" or "yum" or "vmis-launcher" or "pacman" or "apt-get" or "dnf" or "podman" or
platform-python* or "dnf-automatic" or "unattended-upgrade" or "apk" or "snap-update-ns" or "install" or "exe" or
"systemd" or "root" or "sshd" or "pip" or "jlink" or python* or "update-alternatives" or pip* or
"installer.bin.inst" or "uninstall-bin" or "linux_agent.inst" or crio or ssm-agent-worker or packagekitd
"systemd" or "root" or "sshd" or "pip" or "jlink" or python* or "update-alternatives" or pip* or "crio" or
"ssm-agent-worker" or "packagekitd"

@terrancedejesus terrancedejesus Mar 11, 2025

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Can we see if the SSM agent is created the SO because it's running a custom document? If so, this would be very suspicious IMO. AWS-managed SSM docs may do things on Linux systems as a requirement for managing these nodes, however, custom SSM docs can be abused to run whatever on that EC2 instance.

@Aegrah Aegrah Apr 8, 2025

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In this case we just have the file creation event, so all I have is a process name and file path. The file path for this FP pattern is: /usr/lib/jvm/java-17-openjdk-17.0.14.0.7-3.el8.x86_64/lib/{file}.so.

As the pattern is easy to exclude based on process/path, I added the following exclusion (process.name:"ssm-agent-worker" and file.path:/usr/lib/jvm/java*) rather than just on process.name. Thanks for the review @terrancedejesus !

) or
(process.name:vmware-install.pl and file.path:/usr/lib/vmware-tools/*) or
(process.name:"vmware-install.pl" and file.path:/usr/lib/vmware-tools/*) or
process.executable : (/dev/fd/* or "/" or "/kaniko/executor" or "/usr/bin/buildah")
)
'''
Expand Down