Detecting Tampering: How to Protect Ongoing Video Downloads From Process Killers

Hook: When downloads get killed mid-transfer, your workflow—and reputation—can die with them

If you depend on reliable large-file and streaming downloads (archive grabs, long livestream captures, batch media ingestion), a single rogue process kill can wipe hours of progress. In 2026 the risk is higher: low-skill “process-roulette” utilities, misconfigured EDR rules, and AI-assisted malware that targets long-running transfers are all more common. This guide teaches content creators and devops-savvy publishers how to detect process termination, auto-restart downloads safely, validate file integrity, and set up alerts so you know when someone or something tried to break a transfer.

What you'll get: a practical, cross‑platform toolbox

This article gives you concrete recipes for Windows and Linux:

• Watchdog patterns to auto-restart (PowerShell, systemd, supervisord)
• Detection hooks using Sysmon, auditd and eBPF to spot rogue kills
• Integrity strategies to avoid silent corruption and ensure resumptions are safe
• Alerting options from desktop to webhook and SIEM
• Sandboxing and hardening to prevent process killers from having permission to touch downloads

Why this matters in 2026

Two trends shape the problem now. First, adversarial tooling and “process roulette” amusements (and malware variants) surfaced in recent years: tools that intentionally terminate processes make it easier for attackers or pranksters to cause data loss. Second, EDR/anti-virus landscapes have evolved; some endpoints now run third-party mitigations or community patches for end-of-support OSes (for example, community patching approaches gained traction after Windows 10 entered post‑support phases). Both trends mean unexpected process interruptions are more frequent and harder to attribute.

Design principles: build a resilient, observable download pipeline

1. Least privilege: run download processes as an unprivileged user in an isolated environment.
2. Observable: log process lifecycle events and syscall-level kills for post-mortem and real-time alerts.
3. Idempotent restarts: design resume logic and integrity checks so automatic restarts never produce corruption or duplication.
4. Backoff & rate limiting: prevent restart storms if a download repeatedly fails (exponential backoff).
5. Tamper evidence: maintain immutable checksums and consider anchoring them (cloud or append-only log) for critical assets.

Part A — Windows: detect, restart, harden

1) Run your downloader as a managed service

On Windows, the most robust pattern is to run long-running download tools (aria2c, curl, yt-dlp, ffmpeg) under a managed service or a service wrapper. Two practical options:

• NSSM (Non-Sucking Service Manager): quick to setup and supports automatic restarts and logging.
• Windows Service with WinSW (Java/Generic) or a lightweight native service; useful if you need fine-grained credentials.

Service advantages: services can run under a dedicated user, are restarted by Service Control Manager (SCM), and are harder for casual attackers to kill without admin rights.

2) PowerShell watchdog: sample script

If you prefer a scriptable watcher, use PowerShell to monitor a process name/ID and auto-restart on termination. The snippet below demonstrates restart logic with exponential backoff and webhook alerting (replace placeholders):

param($ExePath, $Args, $MaxAttempts=6, $WebhookUrl)

$attempt = 0
$delay = 2
while ($true) {
  $proc = Start-Process -FilePath $ExePath -ArgumentList $Args -PassThru
  Write-Output "Started $($proc.Id)"

  Wait-Process -Id $proc.Id
  $exitCode = $proc.ExitCode
  Write-Output "Process $($proc.Id) exited with $exitCode"

  # Alert:
  Invoke-RestMethod -Uri $WebhookUrl -Method Post -Body (ConvertTo-Json @{id=$proc.Id; exit=$exitCode; time=(Get-Date)}) -ErrorAction SilentlyContinue

  if ($attempt -ge $MaxAttempts) { Write-Output "Max attempts reached, stopping."; break }

  Start-Sleep -Seconds $delay
  $attempt++
  $delay = [Math]::Min($delay*2, 300) # cap at 5 minutes
}

Run this under Task Scheduler as an unprivileged user, or convert to a service with NSSM.

3) Detect who killed the process

Use Sysmon (still essential in 2026) to log process termination events and parent-child relationships. With Sysmon (recent versions), monitor Event ID 5 (Process Terminated) and Event ID 1 (Process Create). Correlate the two to find the killer. Example Sysmon config rule:

<EventFiltering>
  <ProcessTerminate onmatch="include"/>
</EventFiltering>

In your SIEM, alert when a process termination matches unusual parent process names (for instance: process-roulette.exe, task-killer.exe, or unknown signed binaries).

4) Hardening and sandboxing on Windows

• Run downloads in a dedicated non-admin account and use AppLocker/Windows Defender Application Control to block unwanted executables.
• Use Controlled Folder Access to protect download directories from unauthorized modification.
• For high-risk environments, run the downloader inside a lightweight VM or Hyper-V container and export results out only when integrity checks pass.
• Keep endpoint patches and 3rd-party mitigations current; tools like 0patch (community patching) can be helpful when vendors stop supporting old OS versions.
• See guidance on sandboxing and isolation best practices when you need stricter auditability for user-facing tooling.

Part B — Linux: systemd, auditd and eBPF

1) systemd: the canonical watchdog

systemd is perfect for long-running download services because it already provides restart policies, start limits, logging, and watchdog capabilities. Example unit for aria2c:

[Unit]
Description=aria2c download worker
After=network.target

[Service]
User=dluser
Group=dluser
ExecStart=/usr/bin/aria2c --conf-path=/etc/aria2/aria2.conf
Restart=on-failure
RestartSec=10
StartLimitIntervalSec=600
StartLimitBurst=5
StandardOutput=append:/var/log/aria2/aria2.log
StandardError=inherit

[Install]
WantedBy=multi-user.target

This setup enforces backoff and prevents restart loops. systemd exposes status and last exit codes via journalctl for forensic review.

2) Detect kill syscalls: auditd rule

To detect unexpected kill signals on Linux, add an auditd rule to log kill syscall events and target the download user's processes. Example:

auditctl -a exit,always -S kill -F auid>=1000 -F auid!=4294967295 -k process_kill
auditctl -a exit,always -S tkill -k process_kill
auditctl -a exit,always -S tgkill -k process_kill

Audit logs will show the process that invoked the kill and the target PID. Ship audit logs to your SIEM or a central collector and trigger alerts on suspicious activity.

3) eBPF for real-time tracing

Lightweight eBPF scripts (bpftrace or bcc) let you monitor sys_kill and record real-time traces with minimal overhead. Example bpftrace script snippet:

tracepoint:syscalls:sys_enter_kill {
  printf("kill called by pid:%d comm:%s target:%d sig:%d\n", pid, comm, args->pid, args->sig);
}

Run on the host or container runtime to get immediate context when a kill is issued. In 2026 eBPF observability stacks are mainstream and easy to integrate with alerting pipelines.

4) Isolation: unprivileged users, namespaces, and cgroups

Run download jobs in dedicated system users with restricted shell access. For stronger isolation, use user namespaces or container runtimes (Podman, Docker, Firecracker microVM) and limit capabilities (drop CAP_KILL, CAP_SYS_ADMIN). Use cgroups or cgroup v2 to control resource exhaustion attacks that sometimes accompany process-killing routines.

Integrity checks: never trust a resumed file blindly

Restarting a download is only safe if you can validate the resumed state. Follow these safeguards:

• Save remote metadata: When first contacting the source, store ETag, Last-Modified, and Content-Length. Verify these before resume.
• Use server checksums: If the server provides checksums (MD5/SHA256), compare after completion.
• Segment checksums: For segmented downloads (HLS/DASH or multi-connection), compute per-segment hashes and keep a manifest. Resume only segments that failed.
• Container/codec validation: Run ffprobe or mediainfo once the file completes to verify duration, stream counts, and codec sanity.
• Atomic finalization: write to a temporary file and move/rename on successful verification to make the presence of the final file equivalent to “verified”.

Practical examples

curl resume pattern:

# first call: record ETag and size
curl -I https://cdn.example.com/largefile.bin > headers.txt
# later resume
curl -C - -o largefile.part https://cdn.example.com/largefile.bin
# after finish, verify content-length or checksum

aria2 example: aria2 supports --conditional-get and checksums for many protocols. Use per-segment retry parameters so only missing segments are re-fetched.

Alerts: know the moment something tried to stop your job

Choose the alert channels you actually monitor. Options in 2026 are more diverse and privacy-conscious:

• Desktop alerts: Toast/Notification via BurntToast (Windows PowerShell) or notify-send (Linux).
• Webhook integration: Slack, Discord, Microsoft Teams or a custom HTTP endpoint.
• Push services: ntfy, Gotify, Pushover (still popular), or privacy-friendly open-source options (ntfy and local, privacy-first solutions gained traction for lightweight, self-hosted push in 2024–2026).
• SIEM/EDR: ship Sysmon, auditd, and eBPF logs to Elastic, Splunk, or a cloud SIEM and create correlation rules.
• Email/SMS: legacy but useful for on-call workflows (use secure SMTP endpoints or a notification service).

Example: PowerShell toast + webhook (simplified):

Import-Module BurntToast
New-BurntToastNotification -Text "Download watcher", "aria2c stopped: check logs"
Invoke-RestMethod -Uri $WebhookUrl -Method Post -Body (ConvertTo-Json @{service="aria2"; event="stopped"; time=(Get-Date)})

Detecting hostile process killers: analytics & forensics

When you see a termination event, prioritize attribution and prevention:

• Correlate process termination with preceding events: file writes, network connections, or child process creations.
• Search for known indicators: binaries named like ProcessRoulette or task-killer tools; check hashes on VirusTotal or internal YARA rules.
• Check for credential use: was a privileged user involved? If so, rotate credentials and investigate lateral movement.
• Make tamper-evident logs: append-only logs, remote log shipping, or anchored hash lists (upload checksums to S3 / remote object store immediately after a successful download) so you can prove integrity after an incident. For teams building stronger verification pipelines, pair chaos tests with software verification practices in CI.

Operational playbook: step-by-step checklist

1. Create a dedicated download user and directory.
2. Deploy downloader under systemd (Linux) or NSSM/service (Windows).
3. Enable process-termination logging: Sysmon on Windows and auditd/eBPF on Linux.
4. Implement resume-safe download options and save remote metadata (ETag, Last-Modified).
5. Compute per-segment/atomic checksums and verify with ffprobe/mediainfo on completion.
6. Configure alerting to Slack/ntfy/webhook and desktop notifications.
7. Harden with AppLocker/Controlled Folder Access or seccomp/AppArmor and run inside containers/VMs if needed.
8. Test by deliberately killing the process and verifying restarts and integrity checks work as intended.

Advanced strategies and future-proofing

For teams that require stronger assurance:

• Immutable artifacts: Store completed files in WORM-style storage (S3 Object Lock) or use archival WORM volumes to prevent tampering.
• Remote attestation: Publish file fingerprints to a remote anchor (team Git, secured object store, or a ledger) immediately after validation.
• EDR integration: Work with your EDR vendor to whitelist trusted downloader processes and avoid misclassifications that can cause automated kills.
• Chaos testing: Add routine fault injection (controlled process kills) to test watchers and alerting—apply canary runs before major ingest windows. Pair chaos runs with guidance on rapid edge testing and observability when you operate at many edge nodes.
• Consider future compute models and how they affect trust assumptions—experimental hybrid clusters and new attestation models will be part of long-term planning for some teams.

Quick troubleshooting tips

• If a restart loop occurs, check StartLimitBurst / StartLimitIntervalSec (systemd) or implement max attempts in your watcher.
• Correlate local logs with network-level logs—sometimes servers change ETag or rotate CDN nodes, causing resume mismatches.
• If you can’t find the caller of a kill event, increase auditing granularity temporarily (full syscall tracing) and capture a memory image for forensic analysis.

Real-world examples (experience-driven)

Case: a publisher had multi-hour livestream captures that were interrupted by an unknown process on several Windows 10 machines. We hardened the environment by running ffmpeg under NSSM with BurntToast alerts and Sysmon logging. The Sysmon logs revealed a scheduled job named cleanup.exe from a legacy admin tool; after AppLocker rules and a dedicated service account were applied, interruptions stopped and capture integrity improved.

Key takeaways

• Don’t rely on manual restarts: use systemd/services and watchers with backoff to avoid human error.
• Make restarts safe: implement resume-safe logic, per-segment checksums, and atomic finalization.
• Detect the attacker: use Sysmon, auditd and eBPF to identify who or what terminated a transfer.
• Harden and isolate: dedicated users, AppLocker, and containers reduce the attack surface.
• Alert intelligently: integrate desktop alerts, webhooks, and SIEM so you see and act on incidents immediately.

“Automatic restart without integrity checks is a false friend.” — practical rule for resilient media pipelines (2026)

Where to get the scripts and templates

We keep updated, tested templates for systemd units, PowerShell watchers, Sysmon configs, auditd rules, and eBPF snippets in our downloadable repo (link in the CTA below). The repo is updated to reflect 2025–2026 best practices and will include example CI tests for chaos injection.

Final words and call to action

Process killers—malicious or accidental—are an operational reality in 2026. Protecting long-running downloads requires observability, safe restart logic, and careful hardening. Start by wrapping your downloader in a managed service, add integrity checks and per-segment validation, and feed termination events into an alert pipeline. Test with controlled failures and iterate.

Ready to harden your pipeline? Download our ready-to-run PowerShell and systemd templates, plus Sysmon and auditd configs tested against live chaos scenarios. Get them from our repo, subscribe for updates, or contact our team for a configuration review tailored to your workflow.

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