The host 192.168.10.22 is the origin of the infection. The logs for this host at 2:31 PM show "Scheduled scan disabled by process svch0st.exe" and "Scheduled update disabled by process svch0st.exe." This indicates it was the first host to be compromised, allowing the malware to disable its security measures before spreading. The typo "svch0st.exe" is a common malware tactic to mimic a legitimate Windows process, svchost.exe. The hosts 192.168.10.41 and 10.10.9.18 are infected. Their logs show they were unable to quarantine the svch0st.exe file, indicating the infection is active and has bypassed the security software. The hosts 192.168.10.37 and 10.10.9.12 are clean. Their logs show they successfully detected and quarantined the svch0st.exe file, effectively containing the threat before it could compromise the system.

Fortinet. "What is an Attack Vector?". (Provides context on how malware disables security software).

Kaspersky. "Dealing with Svchost.exe Virus' Sneak Attack." (Explains the common malware tactic of mimicking the svchost.exe process).

Secureworks. "A Firewall Log Analysis Primer." (Explains how firewall logs can be used to trace the origin and spread of an infection by analyzing connections and timestamps).

Luo, Wuqiong. "Identifying Infection Sources in a Network." Nanyang Technological University, 2012. (Discusses methodologies for identifying the origin of an infection based on spread patterns and timestamps).