macOS Endpoint Security Engineer

Role: Senior macOS Cyber Security Engineer, Endpoint Security (C++/Swift)
Location: Remote (PST working hours)

Client: Accenture/Amazon
Work Authorization: U.S. Citizen (USC) or Green Card (GC) holders only

Requirement Type: Contractual

Experience: 6-10 years, we can evaluate more senior as well but need to build a pyramid.

Job Description: 

You'll work on the macOS sensor for CrowdStrike Falcon, an on-device security agent. It monitors file, process, network and identity activity, blocks malicious behavior, and streams telemetry to the cloud. The sensor runs entirely in user space as a System Extension. Much of the code is shared with Windows and Linux. The work requires high concurrency, high reliability, careful attention to memory & CPU usage and performance.

Required

· Languages: modern C++ (C++17/20) and Swift 6 (async/await, actors, strict concurrency checking). Also Objective-C++ to bridge Swift, C++ and C APIs.

· macOS systems programming: Foundation and CoreFoundation, GCD and pthreads, POSIX/BSD APIs, Mach IPC, launchd daemons and agents, and XPC (C API and NSXPCConnection).

· Performance, debugging and test:

o Profiling CPU and memory with Instruments and os_signpost.

o Debugging with LLDB, crash logs and os_log.

o XCTest, sanitizers, fuzzing, and xcodebuild-based CI.

o Apple Silicon and Intel.

· Experience with codebases shared across Mac, Windows and Linux.

Core skills (one or more of the areas listed below)

· Process model and IPC: launchd daemons and agents, and XPC (C API and NSXPCConnection).

· Endpoint Security and System Extensions: Endpoint Security clients handling both blocking (AUTH) events and notification events, user/MDM approval, upgrades.

· Network Extension: content filters, both flow-level (NEFilterDataProvider) and packet-level (NEFilterPacketProvider), and Network.framework.

· Security and crypto: Verifying code signatures (SecCode / SecStaticCode) and validating certificates (SecTrust), Keychain, Entitlements, hardened runtime, and macOS privacy permissions.

· Devices and storage: IOKit (hardware and device enumeration) and DiskArbitration (disk and volume events).

· Packaging and deployment: installers, notarization, and MDM configuration profiles deployed through Jamf, Intune or similar tools.

· Performance, debugging and test: Profiling CPU and memory with Instruments and os_signpost, Debugging with LLDB, crash logs and os_log, XCTest, sanitizers, fuzzing, and xcodebuild-based CI.

Nice to have

· UI: SwiftUI and AppKit apps and app extensions.

· Testing against macOS and Xcode betas before public release.

· Experience shipping EDR/AV, network security or device-management products.