falco: tune out calibre sudoers-sed and lsyncd log-truncation false positives
Investigated recent Telegram alerts - no intrusion, both new hits trace to benign one-offs: calibre's linuxserver.io s6-init NOPASSWD setup (same pattern already whitelisted for obsidian) and lsyncd truncating its own status log (not evidence-clearing).
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@@ -9,13 +9,16 @@
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# - pg_isready: fired every ~10s from inbox-zero-db's healthcheck touching
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# /etc/shadow - NSS/libc user-lookup behavior during process init, not
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# credential harvesting.
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# - lscr.io/linuxserver/obsidian: fires once per container start from
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# `sed -i s/CORRUPT_FILE/NOPASSWD/g /etc/sudoers` - linuxserver.io's
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# own s6-init NOPASSWD setup, same class of init-time file touch.
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# - lscr.io/linuxserver/obsidian, lscr.io/linuxserver/calibre: fires once per
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# container start from `sed -i s/CORRUPT_FILE/NOPASSWD/g /etc/sudoers` -
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# linuxserver.io's own s6-init NOPASSWD setup, same class of init-time file
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# touch. Same pattern confirmed on calibre 2026-08-19; scoped per-image
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# rather than by proc.name alone since any other linuxserver.io image will
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# hit this the first time it's added here too.
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- macro: user_known_read_sensitive_files_activities
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condition: >
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(proc.name = pg_isready)
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or (container.image.repository = "lscr.io/linuxserver/obsidian" and proc.name = sed)
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or (container.image.repository in ("lscr.io/linuxserver/obsidian", "lscr.io/linuxserver/calibre") and proc.name = sed)
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# "Fileless execution via memfd_create" fires from nvidia-ctk's
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# ldconfig-refresh hook, which runs via memfd_create by design every time
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@@ -66,3 +69,12 @@
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condition: >
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(container.image.repository = "docker.gitea.com/gitea" and proc.name in (sshd, sshd-session))
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or (container.image.repository = "fireflyiii/core" and proc.cmdline contains "wait-for-it.sh")
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# "Clear Log Activities" false-positive: lsyncd (host systemd service, not a
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# container - running since 2026-07-29) truncates its own status file,
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# /var/log/lsyncd-status.log, as normal self-logging behavior. Matched via
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# the stock rule's fd.directory=/var/log check, not because it's actually
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# clearing evidence. Scoped to that one file, not all of /var/log, so any
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# other log-truncation in that directory still gets flagged.
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- macro: allowed_clear_log_files
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condition: (fd.name = "/var/log/lsyncd-status.log" and proc.name = lsyncd)
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