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Upgrade to ProDetect Data Exfiltration via GitHub Gists and Private Code Repositories in Splunk
Adversaries and malicious insiders increasingly use code-hosting platforms (GitHub, GitLab, Bitbucket) as covert exfiltration channels because traffic to these domains is rarely blocked by web proxies and blends with routine developer activity. Two distinct abuse patterns are observed: (1) anonymous or throwaway-account Gist/paste creation used as a low-friction dead drop for small stolen artifacts (credentials, config files, session tokens) — documented in Turla dead-drop resolver infrastructure and multiple commodity loader families that stage stolen data via the GitHub Gist API before onward retrieval; and (2) bulk exfiltration via `git push` or GitHub API PUT/POST calls to a personal or attacker-controlled repository, seen in APT41 intrusions abusing developer tooling and in Lazarus Group operations staging stolen source code and credentials on GitHub/GitLab ahead of retrieval. The same channel is a leading insider-threat vector: departing employees push proprietary source code or customer data to a personal GitHub account under the cover of routine commits. Detection must distinguish these from the overwhelming volume of legitimate CI/CD and developer git traffic, so the strongest signals are (a) git remotes that do not match the organisation's registered GitHub/GitLab organisation, (b) anonymous Gist creation (no owning account, effectively unlisted/unattributable), and (c) API calls using PUT/POST verbs against content endpoints from processes other than the organisation's recognised CI/CD runners.
MITRE ATT&CK
- Tactic
- Exfiltration
SPL Detection Query
index=wineventlog sourcetype="XmlWinEventLog:Microsoft-Windows-Sysmon/Operational" EventCode=1
(
(Image="*\\git.exe" AND CommandLine="*push*" AND (CommandLine="*github.com*" OR CommandLine="*gitlab.com*" OR CommandLine="*bitbucket.org*") AND NOT CommandLine="*<YOUR_GITHUB_ORG>*")
OR ((Image="*\\curl.exe" OR Image="*\\powershell.exe" OR Image="*\\pwsh.exe" OR Image="*\\python.exe")
AND CommandLine="*api.github.com/gists*"
AND (CommandLine="*POST*" OR CommandLine="*PUT*" OR CommandLine="*Invoke-RestMethod*" OR CommandLine="*Invoke-WebRequest*"))
OR ((Image="*\\curl.exe" OR Image="*\\powershell.exe" OR Image="*\\pwsh.exe" OR Image="*\\python.exe")
AND (CommandLine="*api.github.com*" OR CommandLine="*api.gitlab.com*" OR CommandLine="*api.bitbucket.org*")
AND (CommandLine="*/contents/*" OR CommandLine="*/repos/*")
AND (CommandLine="*PUT*" OR CommandLine="*POST*"))
)
| eval Signal=case(
match(CommandLine, "(?i)push"), "GitPushNonCorpRemote",
match(CommandLine, "(?i)gists"), "AnonGistCreate",
true(), "ContentsApiUpload"
)
| stats count AS Events, values(CommandLine) AS Commands BY host, User, Image, Signal
| sort - EventsSPL detection over Sysmon process creation for the same three signals as the KQL query: git push to a non-corporate remote, anonymous Gist API creation via scripting engines, and direct Contents/Repos API uploads. Requires the `<YOUR_GITHUB_ORG>` placeholder to be replaced with the deployment's actual GitHub/GitLab organisation name during onboarding.
Data Sources
Required Sourcetypes
False Positives & Tuning
- Legitimate personal-fork pushes by developers contributing to open-source projects
- DevRel/security research accounts publishing sanctioned public Gists
Other platforms for THREAT-CodeRepo-GistExfil
Testing Methodology
Validate this detection against 2 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Simulate Exfiltration via Anonymous GitHub Gist
Expected signal: Sysmon Event ID 1: curl.exe process creation with command line referencing api.github.com/gists and a POST body.
- Test 2Simulate Exfiltration via Git Push to Non-Corporate Remote
Expected signal: Process creation events for git with 'push' in the command line and a remote URL not matching the corporate org.
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