Mobile Apps Security Engineer

The opportunity #

Cossack Labs is looking for a Mobile apps security engineer to join our Security team and work with us on building and breaking software. If you are interested in designing and building security controls, working hand-in-hand with software developers, performing security assessments, this may be the position for you!

We are a data security solutions company, developing software products (open-source and proprietary), as well as providing custom bespoke solutions to innovative development teams around the world. Our mission is to make strong security methodologies and approaches convenient within modern infrastructures and, as the software is eating the world, help it eat the world responsibly, without leaking customer’s data.

Our software is well-known amongst security-aware teams, recommended by OWASP, and popular for easily solving complicated security challenges. Apart from building “off-the-shelf” solutions, we design custom security controls for novel problems.

We work in the B2B space, with customers such as power grid operators, payment processors, legal companies, million-user customer applications. We cater to young ambitious startups and well-established enterprises, who use our software and solutions as core part of their security arsenal. Our customers are smart, but extremely demanding.

Markets: EU, UK, USA.

You will: #

• Participate in security assessments of mobile applications (iOS, Android, Flutter, React Native). Focus on platform-specific security controls (biometrics, security storage, device capabilities). Perform analysis and threat modelling.
• Design, implement and validate reverse engineering protections using vendor-provided API (DeviceCheck, AppAttest, Play Integrity API) as well as community wisdom (debug-detection, jailbreak/root detection).
• Treat mobile app as a gateway into a larger system, build security defences from app to the backend and back (transport protections, TLS pinning, anti-fraud systems).
• Participate in SSDLC for our products and our customers’ products: design, implementation and review of security controls. Assist and guide developers in securing data and software (explain risks & threats, work together to select security controls that would improve security without restricting usability/performance).
• Assist us in maintaining our software for mobile, for example, Themis cryptography library works on multiple platforms, as requires a bit of love and testing with each new Xcode update.
• Stay up to date with emerging security threats, vulnerabilities, and controls (read articles and papers, follow CVE updates, understand how threat landscape is changing, understand how to apply described ideas, read NIST guidelines).
• Work with security across different stack: mobile and web applications, cloud and on-prem infrastructures, hardware devices, etc. Dive into application security, infrastructure security, data security, IoT security, ML security with our team of skilled engineers. See related case study, written from an engineer’s point of view.
• Share your work as conference talks, blogposts (see React Native security example), contribute to open source standards like OWASP.

We would expect you to have: #

• Ability to read code, understand business logic and spot security mistakes in different mobile-relevant languages, like Swift, Objective-C, Kotlin, Java, JavaScript, TypeScript, Dart.
• Experience designing and implementing mobile security controls, as well as platform-specific controls (Biometry on iOS, screenshot protections on Android, etc).
• Good understanding of OWASP MAS (MASVS + MASTG).
• Be familiar with other application security verification and software maturity frameworks: OWASP SAMM, OWASP ASVS.
• Understanding SSDLC and its difficulties. OWASP SSDLC, NIST SSDF.
• Experience in performing security assessment for mobile and/or web applications.
• Understanding how computers, internet and mobile devices work.
• An overall understanding of what information security is, how real-world risks and threats affect the choice of security controls. How to combine detective, detective and corrective controls.

As a plus you’d have #

• Mobile development experience, experience in building and releasing your own apps. Experience with popular mobile stack: Xcode, Android Studio,TestFlight, Firebase, AppCenter, Bitrise, fastlane, etc.
• Experience in jailbreaking/rooting your devices.
• Experience in reverse engineering applications, bypassing TLS pinning, analysing source code.
• Basic knowledge in cryptography: understanding the differences between symmetric and asymmetric cryptography, hashing, KDF.
• Knowledge in one of several business domains: banking / finance / payment processing, cryptocurrencies.

Please note that you can be a perfect fit even if not everything we’ve outlined above applies to you. If you have any questions, please don’t hesitate to ask – everyone is unique.

We offer: #

Unique area of expertise: #

• Interesting and challenging work in applied security engineering: from building to breaking. Working at the intersection of different areas: designing ML security controls, supporting cryptographic protocols with security controls, protecting hardware, building reverse-resilient mobile apps, securing web apps for million of users, etc.
• Public track record in the open source part of our products, sharing your work as blogs posts, research papers and conference talks. We work with innovative companies all over the world, move quickly and dive into technologies others just hear about.
• Work at the intersection of technologies: cryptography, software engineering, information security. You won’t be bored :)
• A sense of meaning and responsibility for those who seek purpose – we’re building “invisible texture of modern civilization”—bits of infrastructure finance, power grids, healthcare rely on, and we are trusted with very challenging aspects of it.

Environment: #

• Friendly and experienced team: smart people to learn from, great people to build with. Each of us is unique, we value and support each other.
• An atmosphere that motivates you to grow and get smarter every month, a healthy ratio of routine / experimentation.
• Trust: schedule, reporting, bureaucracy is kept at reasonable minimum. We hire smart people and trust them to do the right thing. When things go wrong, we help rather than punish.
• Shared decision making: this business is driven by engineering excellence, so engineers are important part of tactical and strategical business decisions.
• Friendly to humans: not just a formal vacation and sick leave quota. Feel like your mental or physical wellbeing needs care? Take some time off. Feel like working a few days from home? Sure. As long as you’re in line, we are here to support you when you’re not.

Growth: #

• Team that facilitates internal learning and growth all the time.
• Interesting technologies to work with — sometimes, even unique ones (we design applied cryptography schemes and techniques and novel ways to use them).
• Interesting engineering challenges across the board, ability to hop from high-level system design to protocol reverse engineering and clever data modelling hacks.
• Management attention to help you improve upon your personal goals (through regular 1:1s and mentoring).

Benefits: #

• Competitive compensation with flexible bonus scheme.
• Sick leaves, 21 vacation days a year, extra days off — according to agreements and laws.
• Conferences, books, courses — we encourage learning and sharing with the community. Our team members share a lot in talks, workshops and blog posts.

Not sure but considering? Talk to us. #

If you see yourself fit but a few things are off — don’t hesitate to talk anyway. It might be that your unique combination of skills and knowledge would be perfectly fitting for our environment, but we both just don’t know it yet.