Senior Mobile Security Engineer (Offensive)

Klarna; Greater London; Hybrid; GBP 120,000 - 190,000; Full time

Job summary

Klarna is seeking an offensive mobile security specialist in London to perform pentests and red-team exercises against its iOS and Android apps. You will reverse-engineer binaries, evaluate app hardening, and collaborate with engineering to turn findings into fixes.

You should have hands-on mobile security experience, strong MASVS/MASTG knowledge, and familiarity with Frida, Burp, MobSF, and related tools. This role offers a hybrid work setup with office presence in London.

Qualifications

• Hands-on mobile security testing against iOS/Android via pentesting or red-teaming.
• Fluent with MASVS/MASTG as reference frameworks.
• Strong knowledge of mobile security tooling and app hardening.
• Experience with fintech or production mobile apps is a bonus.

Responsibilities

• Run offensive security assessments on Klarna's iOS and Android apps.
• Reverse-engineer app binaries to surface sandboxing and permission weaknesses.
• Test Klarna's mobile apps against MASVS and MASTG and drive fixes with engineering teams.
• Evaluate and stress-test app-hardening and RASP protections with the teams.
• Document findings clearly and ensure fixes are implemented.

Skills

Offensive security

Penetration testing

Red-team exercises

Bug bounty

Tools

Frida

Objection

MobSF

jadx

apktool

Ghidra

Hopper

Burp Suite

mitmproxy

Job description

Klarna is seeking an offensive mobile security specialist in London to perform pentests and red-team exercises against its iOS and Android apps. You will reverse-engineer binaries, evaluate app hardening, and collaborate with engineering to turn findings into fixes.

You should have hands-on mobile security experience, strong MASVS/MASTG knowledge, and familiarity with Frida, Burp, MobSF, and related tools. This role offers a hybrid work setup with office presence in London.