Detect Develop Capabilities in Elastic Security
This detection identifies indicators that adversaries have deployed custom-developed capabilities within the target environment. Because T1587 (Develop Capabilities) occurs outside the victim network during the adversary lifecycle, direct detection is impossible; instead, this rule focuses on second-order indicators: unsigned or self-signed executables executing from non-standard paths, low-prevalence binaries making network connections, and novel tooling patterns associated with bespoke malware frameworks. Groups such as Kimsuky, Moonstone Sleet, and Contagious Interview are known to develop custom tools—including malicious NPM packages, spearphishing toolkits, and custom implants—that exhibit these characteristics upon deployment. The detection correlates signature anomalies, environmental prevalence, and behavioral signals to surface likely custom-developed tools used in targeted intrusions.
MITRE ATT&CK
- Tactic
- Resource Development
- Technique
- T1587 Develop Capabilities
- Canonical reference
- https://attack.mitre.org/techniques/T1587/
Elastic Detection Query
sequence by process.executable with maxspan=1h
[process where event.type == "start"
and not process.executable : ("C:\\Windows\\System32\\*", "C:\\Windows\\SysWOW64\\*", "C:\\Program Files\\*", "C:\\Program Files (x86)\\*", "C:\\Windows\\WinSxS\\*")
and process.code_signature.trusted == false
and (
process.executable : "*\\AppData\\Local\\Temp\\*" or
process.executable : "*\\Downloads\\*" or
process.executable : "*\\ProgramData\\*" or
process.executable : "C:\\Temp\\*" or
process.executable : "C:\\Windows\\Temp\\*"
)
] by process.pid
[network where event.type == "connection" and not cidrmatch(destination.ip, "10.0.0.0/8", "172.16.0.0/12", "192.168.0.0/16", "127.0.0.0/8")
] by process.pidDetects unsigned or untrusted executables launching from non-standard paths that subsequently make outbound network connections to external IPs — a strong indicator of custom-developed implants associated with T1587. Correlates process start events with outbound network activity using ECS fields and EQL sequence correlation.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate developer toolchains (Go, Rust, Python) compiling and immediately running binaries from temp directories during CI/CD pipelines
- Portable applications (e.g., PortableApps) executed from Downloads that reach out for update checks
- Security scanning tools or penetration testing frameworks run from non-standard paths by authorised red team operators
Other platforms for T1587
Testing Methodology
Validate this detection against 3 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 1Execute Self-Signed Binary from User-Writable Path (Windows)
Expected signal: DeviceProcessEvents: FileName=custom_capability_test.exe, ProcessSignatureStatus=SignedByUntrustedCertificate, FolderPath contains \AppData\Local\Temp. DeviceImageLoadEvents showing DLLs loaded with self-signed parent process.
- Test 2Deploy Malicious NPM Post-Install Script (Cross-Platform)
Expected signal: Sysmon EventCode=1 (Linux auditd execve): process spawned with ParentImage=/usr/bin/node, Image=/bin/sh or /bin/id. audit.log entries showing execve syscall from node process with working directory in node_modules path.
- Test 3Compile and Execute Custom ELF Binary with Network Connection (Linux)
Expected signal: auditd: EXECVE record for /tmp/atomic_custom_tool with ppid matching shell. SOCKADDR audit record showing connect() call to 192.0.2.1:4444. Sysmon for Linux EventCode=3 (Network Connect) if deployed. /proc/<pid>/exe pointing to /tmp path.
References (8)
- https://attack.mitre.org/techniques/T1587/
- https://www.mandiant.com/resources/apt1-exposing-one-of-chinas-cyber-espionage-units
- https://securelist.com/sofacy-apt-hits-high-profile-targets-with-updated-toolset/72924/
- https://www.bitdefender.com/files/News/CaseStudies/study/353/Bitdefender-Whitepaper-StrongPity-APT.pdf
- https://blog.talosintelligence.com/2020/06/promethium-extends-with-strongpity3.html
- https://www.microsoft.com/en-us/security/blog/2024/05/28/moonstone-sleet-emerges-as-new-north-korean-threat-actor/
- https://www.sentinelone.com/labs/contagious-interview-clickfix-reloaded-threat-actor-deploys-new-malware-via-fake-video-conferencing-apps/
- https://virusbulletin.com/virusbulletin/2019/10/kimsuky-apt-group/
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