# [HIGH] Build a software bill of materials (SBOM) for open source supply chain security **Source:** Snyk **Published:** 2022-03-14 **Article:** https://snyk.io/blog/building-sbom-open-source-supply-chain-security/ ## Threat Profile Snyk Blog In this article Written by Liran Tal March 14, 2022 0 mins read More than ever, developers are building web applications on the foundations of open source software libraries. However, while those libraries make up the software bill of materials (SBOM) components inventory, not all developers and business stakeholders understand the significant impact on open source supply chain security that stems from including 3rd party libraries. With this in mind, let’s explore the topic of SBOM s… ## Indicators of Compromise (high-fidelity only) - _No high-fidelity IOCs in the RSS summary._ If the source publishes a technical write-up with defanged IOCs in the body, those would be picked up automatically on the next pipeline run. ## MITRE ATT&CK Techniques - **T1566.002** — Spearphishing Link - **T1204.001** — User Execution: Malicious Link - **T1059.001** — PowerShell - **T1204.004** — User Execution: Malicious Copy and Paste - **T1195.002** — Compromise Software Supply Chain - **T1204.002** — User Execution: Malicious File ## Kill chain phases observed _(none detected from narrative keywords)_ ## Recommended hunts ### Phishing-link click correlated to endpoint execution `UC_PHISH_LINK` · phase: **delivery** · confidence: **High** **Splunk SPL (CIM):** ```spl ``` Phishing-link click that drives endpoint execution within 60s ``` | tstats `summariesonly` earliest(_time) AS click_time from datamodel=Web where Web.action="allowed" by Web.src, Web.user, Web.dest, Web.url | `drop_dm_object_name(Web)` | rename user AS recipient, dest AS clicked_domain, url AS clicked_url | join type=inner recipient [| tstats `summariesonly` count from datamodel=Email.All_Email where All_Email.action="delivered" AND All_Email.url!="-" by All_Email.recipient, All_Email.src_user, All_Email.url, All_Email.subject | `drop_dm_object_name(All_Email)` | rex field=url "https?://(?[^/]+)" | rename recipient AS recipient] | join type=inner src [| tstats `summariesonly` earliest(_time) AS exec_time values(Processes.process) AS exec_cmd, values(Processes.process_name) AS exec_proc from datamodel=Endpoint.Processes where Processes.parent_process_name IN ("chrome.exe","msedge.exe","firefox.exe", "outlook.exe","brave.exe","arc.exe") AND Processes.process_name IN ("powershell.exe","pwsh.exe","cmd.exe","mshta.exe", "rundll32.exe","regsvr32.exe","wscript.exe", "cscript.exe","bitsadmin.exe","certutil.exe", "curl.exe","wget.exe") by Processes.dest, Processes.user | `drop_dm_object_name(Processes)` | rename dest AS src] | eval delta_sec = exec_time - click_time | where delta_sec >= 0 AND delta_sec <= 60 | table click_time, exec_time, delta_sec, recipient, src, src_user, subject, clicked_domain, clicked_url, exec_proc, exec_cmd | sort - click_time ``` **Defender KQL:** ```kql // Phishing-link click that drives endpoint execution within 60s. // Far higher fidelity than "every clicked URL" — most legitimate clicks // never spawn a non-browser child process, so the join eliminates the // 99% of noise that makes a raw click query unactionable. let LookbackDays = 7d; let SuspectClicks = UrlClickEvents | where Timestamp > ago(LookbackDays) | where AccountName !endswith "$" | where ActionType in ("ClickAllowed","ClickedThrough") | join kind=inner ( EmailEvents | where Timestamp > ago(LookbackDays) | where DeliveryAction == "Delivered" | where EmailDirection == "Inbound" | project NetworkMessageId, Subject, SenderFromAddress, SenderFromDomain, RecipientEmailAddress, EmailTimestamp = Timestamp ) on NetworkMessageId | join kind=leftouter ( EmailUrlInfo | project NetworkMessageId, Url, UrlDomain ) on NetworkMessageId, Url | project ClickTime = Timestamp, AccountUpn, IPAddress, Url, UrlDomain, Subject, SenderFromAddress, SenderFromDomain, RecipientEmailAddress, ActionType; // Correlate to a non-browser child process spawned within 60 seconds on // the recipient's device. DeviceProcessEvents | where Timestamp > ago(LookbackDays) | where InitiatingProcessFileName in~ ("chrome.exe","msedge.exe","firefox.exe", "outlook.exe","brave.exe","arc.exe") | where FileName in~ ("powershell.exe","pwsh.exe","cmd.exe","mshta.exe", "rundll32.exe","regsvr32.exe","wscript.exe","cscript.exe", "bitsadmin.exe","certutil.exe","curl.exe","wget.exe") | join kind=inner SuspectClicks on $left.AccountName == $right.AccountUpn | where Timestamp between (ClickTime .. ClickTime + 60s) | project ClickTime, ProcessTime = Timestamp, DelaySec = datetime_diff('second', Timestamp, ClickTime), DeviceName, AccountName, RecipientEmailAddress, SenderFromAddress, Subject, Url, UrlDomain, ActionType, FileName, ProcessCommandLine, InitiatingProcessFileName | order by ClickTime desc ``` ### Fake CAPTCHA / clipboard-injected PowerShell (ClickFix / FakeCaptcha) `UC_FAKECAPTCHA` · phase: **exploit** · confidence: **High** **Splunk SPL (CIM):** ```spl | tstats `summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name IN ("explorer.exe","RuntimeBroker.exe") AND Processes.process_name IN ("powershell.exe","pwsh.exe","mshta.exe") AND (Processes.process="*iex*" OR Processes.process="*Invoke-Expression*" OR Processes.process="*FromBase64*" OR Processes.process="*DownloadString*" OR Processes.process="*hxxp*" OR Processes.process="*curl*" OR Processes.process="*wget*") by Processes.dest, Processes.user, Processes.process, Processes.parent_process_name | `drop_dm_object_name(Processes)` ``` **Defender KQL:** ```kql DeviceProcessEvents | where Timestamp > ago(7d) | where AccountName !endswith "$" | where InitiatingProcessFileName in~ ("explorer.exe","RuntimeBroker.exe") | where FileName in~ ("powershell.exe","pwsh.exe","mshta.exe") | where ProcessCommandLine matches regex @"(?i)(iex|invoke-expression|frombase64|downloadstring|hxxp|curl |wget )" | project Timestamp, DeviceName, AccountName, ProcessCommandLine, InitiatingProcessCommandLine ``` ### Trusted vendor binary / installer launching unusual children `UC_SUPPLY_CHAIN` · phase: **exploit** · confidence: **Medium** **Splunk SPL (CIM):** ```spl | tstats `summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name IN ("setup.exe","installer.exe","update.exe") AND Processes.process_name IN ("powershell.exe","cmd.exe","rundll32.exe","regsvr32.exe","mshta.exe","wscript.exe","cscript.exe","wmic.exe","bitsadmin.exe") by Processes.dest, Processes.user, Processes.parent_process_name, Processes.process_name, Processes.process | `drop_dm_object_name(Processes)` ``` **Defender KQL:** ```kql DeviceProcessEvents | where Timestamp > ago(7d) | where AccountName !endswith "$" | where InitiatingProcessFileName in~ ("setup.exe","installer.exe","update.exe") | where FileName in~ ("powershell.exe","cmd.exe","rundll32.exe","regsvr32.exe","mshta.exe","wscript.exe","cscript.exe","wmic.exe","bitsadmin.exe") | project Timestamp, DeviceName, AccountName, InitiatingProcessFileName, FileName, ProcessCommandLine ``` ### Article-specific behavioural hunt — Build a software bill of materials (SBOM) for open source supply chain security `UC_2305_3` · phase: **exploit** · confidence: **High** **Splunk SPL (CIM):** ```spl ``` Article-specific bespoke detection — Build a software bill of materials (SBOM) for open source supply chain security ``` | tstats `summariesonly` count earliest(_time) AS firstTime latest(_time) AS lastTime from datamodel=Endpoint.Processes where (Processes.process_name IN ("node.js")) by Processes.dest, Processes.user, Processes.process_name, Processes.process, Processes.parent_process_name, Processes.process_path | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | append [ | tstats `summariesonly` count from datamodel=Endpoint.Filesystem where Filesystem.action IN ("created","modified") AND (Filesystem.file_name IN ("node.js")) by Filesystem.dest, Filesystem.user, Filesystem.process_name, Filesystem.file_path, Filesystem.file_name | `drop_dm_object_name(Filesystem)` ] ``` **Defender KQL:** ```kql // Article-specific bespoke detection — Build a software bill of materials (SBOM) for open source supply chain security // Hunts the actual binaries / paths / commandline fragments named // in the article instead of a generic technique-class template. DeviceProcessEvents | where Timestamp > ago(30d) | where (FileName in~ ("node.js")) | project Timestamp, DeviceName, AccountName, FileName, FolderPath, ProcessCommandLine, InitiatingProcessFileName, InitiatingProcessCommandLine | order by Timestamp desc // File-creation events for the named binaries / paths DeviceFileEvents | where Timestamp > ago(30d) | where ActionType in ("FileCreated","FileModified") | where (FileName in~ ("node.js")) | project Timestamp, DeviceName, AccountName, FolderPath, FileName, ActionType, InitiatingProcessFileName, InitiatingProcessCommandLine | order by Timestamp desc ``` ## Why this matters Severity classified as **HIGH** based on: 4 use case(s) fired, 6 technique(s) inferred. Read the full article for actor attribution, tooling details, and any defanged IOCs in the body that aren't visible in the RSS summary.