The SANS Institute is pushing deeper into offensive security training with its SEC670 course, “Red Teaming Tools – Developing Windows Implants, Shellcode, Command and Control,” giving experienced practitioners hands-on practice in building stealthy Windows malware. The class focuses on writing custom implants and evasive payloads rather than reverse-engineering them, a perspective that mirrors real-world attacker tradecraft and is designed to sharpen both red- and blue-team skills.
According to SANS, SEC670 teaches students how to develop Windows implants, shellcode and command-and-control frameworks that are capable of evading modern defensive controls, including EDR and endpoint antivirus tools, while also covering techniques for operational security and payload delivery in realistic scenarios (SEC670 course description). The course is positioned as a follow-on for practitioners who have already completed malware analysis tracks such as FOR610, “Reverse-Engineering Malware: Malware Analysis Tools and Techniques,” and FOR710, “Reverse-Engineering Malware: Advanced Code Analysis,” which approach the problem from the defender’s side (FOR610) (FOR710).
One of the techniques highlighted in the training is the use of stack strings, in which malware authors construct strings at runtime on the stack instead of storing them as static, null-terminated strings in the binary’s data segment. By breaking up and reassembling critical values such as API names, file paths or C2 URLs, stack strings can make it significantly harder for static scanners and YARA rules to identify malicious code through string-based signatures. This obfuscation approach aligns with tactics documented in the MITRE ATT&CK framework under T1027 (Obfuscated/Encrypted Payloads), which describes how adversaries modify or hide code and data to impede analysis.
The growing emphasis on these techniques in formal training reflects how common they have become in the wild. Modern malware families and advanced persistent threat (APT) toolsets routinely employ stack strings and related string-obfuscation methods to evade detection during static triage in sandboxes, email gateways and repository scans. As more red-team operators are trained to build bespoke implants with these capabilities, defenders can expect to face more campaigns where traditional string-based indicators are sparse or completely absent, forcing a greater reliance on behavioral analytics and memory forensics.
For defenders, courses like SEC670 are a double-edged sword: they help red teams more accurately emulate sophisticated adversaries, but they also provide blue teams with a roadmap of what to hunt for. Incident responders and threat hunters who understand stack-string implementations can enhance YARA and memory-scanning rules to look for telltale patterns of runtime string construction, such as sequences of push and mov instructions or immediate values that decode to suspicious API names once reconstructed. Coupled with telemetry on process injection, anomalous API usage and unusual outbound network activity, this knowledge can improve detection of implants that seek to hide in plain sight.
Security leaders considering the course are increasingly pairing SEC670 with the FOR610 and FOR710 reverse-engineering tracks to give teams a full lifecycle view of malware, from design and development through analysis and response. That combination underscores a broader industry shift: defenders who understand how implants are built, not just how they behave after the fact, are better positioned to anticipate attacker innovation and to design controls that remain effective even as offensive techniques like stack strings and advanced obfuscation become standard fare.
