KnockKnock Flagging Unknown Launch Items While macOS Reports No Malware — The Forensics Steps That Resolved False Alarms

For cybersecurity professionals and privacy-conscious Mac users, KnockKnock by Objective-See is a trusted tool that surfaces persistent items—programs or scripts set to run at startup—which may otherwise go unnoticed. However, when KnockKnock flags unfamiliar launch items that macOS itself reports as benign or non-malicious, it raises an uncomfortable specter: false positives cloaked in ambiguity. What happens when your diagnostic tools don’t agree? In this article, we walk you through the investigation, forensics, and conclusion of a case where KnockKnock reported unknown launch items, prompting an in-depth examination that ultimately revealed a harmless source.

TL;DR

KnockKnock flagged unfamiliar launch agents that turned out to be from recently installed, legitimate software. macOS’s built-in security systems—including XProtect and Malware Removal Tool (MRT)—detected no threats. A structured forensic analysis confirmed the items were safe and the alerts were false positives. A combination of file-hash validation, developer signature checks, and baseline comparisons resolved the issue conclusively.

Understanding KnockKnock’s Role in Persistent Items Analysis

KnockKnock is an investigative tool, not an active protection layer. Developed by Patrick Wardle—a respected authority in macOS security—KnockKnock scans areas of disk and memory where persistent execution hooks commonly reside: launch agents, kernel extensions, login items, and more.

When KnockKnock flags a launch item as “unknown”, this typically means it doesn’t recognize the binary from a list of known system files or trusted third-party entities. This doesn’t equate to it being malware, but it does mean manual investigation should follow.

Initial Findings: Suspicious But Not Malicious

This case began with KnockKnock reporting two unknown launch items located in:

• ~/Library/LaunchAgents
• /Library/LaunchDaemons

These items had generic-looking names, lacked immediate correlation to known apps, and were not accompanied by readable documentation. However, no security dialogs had appeared during use, nor did macOS raise any alerts.

macOS was up to date with all enabled protection layers:

• XProtect
• Malware Removal Tool (MRT)
• System Integrity Protection (SIP)
• Gatekeeper

Still, the presence of these mysterious launch items required deeper analysis.

Step 1: Verify Trust and Check for Code Signatures

First, we collected metadata using command-line utilities. The focus was on verifying whether these binaries were signed and, if so, by whom.

Command used:

codesign -dvvv /path/to/binary

Both targets were digitally signed by a known and verified Apple developer ID. This is an important green flag, though not definitive. Threat actors can, and occasionally do, obtain developer credentials fraudulently.

Result: Signed binaries with valid entitlements, consistent with recently installed software.

Step 2: Hash Matching Against Online Databases

To cross-reference the legitimacy and reputation of these binaries, we calculated SHA-256 hashes and searched them on multiple repositories:

• VirusTotal
• Hybrid Analysis
• Objective-See’s database

Command used:

shasum -a 256 /path/to/binary

None of the hashes returned malicious classifications. VirusTotal reported them as originating from a known software company offering productivity enhancements for macOS, recently installed by the system user.

Conclusion: No malicious footprint in global threat intelligence databases.

Step 3: Analyze Launch Agent Contents

Each suspicious launch item had an associated .plist file. We examined these using the plutil and cat commands to determine how the launch items operated:

cat ~/Library/LaunchAgents/com.example.agent.plist

Entries revealed typical configuration keys:

• Label: Custom but human-readable
• ProgramArguments: Executables in a subfolder of the global Applications library
• RunAtLoad: true

This indicated the processes were designed to initiate at user login, but had no obfuscation or redirection often disguised in malware.

Result: Behavior consistent with helper tools or auto-updaters.

Step 4: Time of Installation and Persistence Creation

An important part of forensic diligence is understanding when the item appeared. Using macOS audit logs and the filesystem creation time, we validated timestamps:

• Launch agent files created 48 hours prior
• System install logs showed a corresponding app installation
• User confirmed this software installation

Tool used: ls -lt and log show --predicate

Outcome: High correlation between software install event and launch item creation. Suggests intentional setup, not surreptitious behavior.

Step 5: Compare to Known Good State (Binary Baseline)

To confirm findings, we obtained the same software on a test macOS device and installed it in a sandboxed environment. Immediately, the same launch items emerged with identical file names and hash values.

This validation step confirmed that:

• The flagged items are part of the legitimate installation process
• No alterations occurred post-installation
• macOS notarization and transparency logs backed the developer’s credibility

Why Did KnockKnock Flag It?

KnockKnock by design is intentionally cautious. It operates on heuristic rules and local whitelist models. If a launch item doesn’t map to Apple’s known binaries or hasn’t been previously cataloged, it will show up labeled as “unknown.”

This makes KnockKnock a tool that exposes opportunity for further inspection—not one that makes final malware determinations. It is particularly useful for investigators or sysadmins creating baselines or hardening postures.

When “Unknown” Doesn’t Mean “Danger”

This case, like many, speaks to a growing challenge in modern digital incident response: distinguishing unknown from malicious. Automated tools don’t always make that distinction clearly, yet teams must react appropriately without causing unnecessary alarm.

Decoding why a file is labeled unknown often involves layers of analysis. The key takeaways from our exercise were:

• Trust—but verify—digital signatures
• Correlate artifacts with user and system activity
• Utilize threat intelligence resources
• Never delete first—understand behavior before acting

Conclusion

False positives are an unavoidable part of modern cybersecurity tooling. In this scenario, KnockKnock accurately surfaced a new persistent item not yet cataloged, but all forensic evidence indicated it was safe. The macOS native defenses, combined with methodical forensics, confirmed that there was no malicious behavior.

Security is not just about detection—it’s about measured, well-informed reaction. Tools like KnockKnock serve as essential sentinels, but professional assessment remains essential for final judgment. As systems grow more complex, so too must the rigor of our investigative processes.