AN0178
Analytic 0178
Windows
Behavioral chain: (1) a user-facing app (browser/Office/email client) launches a URL or handles a link, then (2) the same process lineage makes an outbound connection to an untrusted domain/IP, (3) a file is downloaded or unpacked to a user-writable location shortly after the click. Optional enrichment: subsequent child execution by LOLBINs.
WinEventLog:Security
EventCode=4688
WinEventLog:Sysmon
EventCode=3, 22
WinEventLog:Sysmon
EventCode=11
NSM:Flow
Suspicious URL patterns, uncommon TLDs, short-lived domains, URL shorteners; HTTP method GET/POST
[TimeWindow]
Correlation window (e.g., 15m) between link click / first egress / file write.
[BrowserParents]
Processes considered link sources: chrome.exe, msedge.exe, firefox.exe, winword.exe, outlook.exe, teams.exe.
[UserPaths]
User-writable directories to monitor (%USERPROFILE%\Downloads, %TEMP%, %APPDATA%\*, OneDrive caches).
[SuspiciousTLDs]
High-risk TLD and domain list (e.g., .top .xyz .monster; newly observed domains/NOD).
[AllowedCDNs]
Corporate CDNs/update hosts to reduce false positives.
AN0179
Analytic 0179
Linux
Behavioral chain: (1) browser/office/GUI mail client opens a URL, (2) outbound connection to untrusted domain, (3) a new file is saved in $HOME/Downloads, /tmp, or cache immediately after.
auditd:SYSCALL
execve: Execs of chromium, google-chrome, firefox, libreoffice with http(s) in cmdline
auditd:SYSCALL
open,creat,rename: Writes in $HOME/Downloads, /tmp, ~/.cache with exe/script/archive/office extensions
NSM:Flow
Suspicious URL patterns, uncommon TLDs, URL shorteners
[TimeWindow]
Typical 10–20m between click and write.
[UserPaths]
$HOME/Downloads, /tmp, ~/.cache, ~/.local/share.
[HighRiskExtensions]
exe, elf, sh, js, py, jar, iso, img, zip, rar, xlsm, docm, xll.
[DomainRiskScore]
Heuristic or TI score threshold for domains.
AN0180
Analytic 0180
macOS
Behavioral chain: (1) Safari/Chrome/Firefox/Office handles a URL; unified logs show open/click or LSQuarantine assignment, (2) outbound connection to untrusted domain, (3) a new file appears in ~/Downloads or /private/var/folders/* with quarantine flag.
macos:unifiedlog
open URL|clicked link|LSQuarantineAttach
NSM:Connections
New outbound connection from Safari/Chrome/Firefox/Word
fs:fsevents
Create in /Users/*/Downloads or /private/var/folders/* with quarantine attribute
[TimeWindow]
10–30m correlation.
[QuarantinePolicy]
Alert when com.apple.quarantine missing on newly downloaded executables.
[SuspiciousTLDs]
Org-specific risky domains/TLDs.