Senior Offensive Security Engineer (Web & API)

Applaudo; Argentina; Hybrid; ARS 16,740,000 - 27,900,000; Part time

Job summary

Applaudo seeks an experienced offensive security professional to perform controlled production testing of web apps, REST/SOAP APIs, and API gateways. You will validate vulnerabilities via exploitation with clear, reproducible evidence and report in English during weekly client calls.

The contractor role spans an initial 2 months with potential extension; strong focus on testing in production with strict stop conditions and regulatory-ready documentation.

Qualifications

• 5+ years of hands on penetration testing, incl. 3+ years web apps and APIs in production.
• Manual testing aligned to OWASP WSTG, OWASP Top 10 and OWASP API Security Top 10.
• Burp Suite Pro experience with SOAP/WSDL testing.
• Authorization testing across multi-role accounts in SSO protected apps (Entra ID, OAuth2, OIDC, SAML).
• External reconnaissance and attack surface enumeration with Amass, subfinder, httpx or equivalents.

Responsibilities

• Perform outside unauthenticated testing of in-scope web apps, REST and SOAP APIs, API gateway and internet-exposed hosts.
• Conduct inside testing from client-provided accounts, covering cross-role authorization and privilege escalation.
• Discover API specifications OpenAPI, WSDL and Postman collections when required.
• Document findings with exploitation evidence and reproduce results for regulatory review.
• Score findings using CVSS v3.1 and prepare attestation letters covering outside/inside perspectives.

Skills

Penetration testing

Web applications

APIs

OWASP WSTG

SSO testing

Burp Suite

OpenID Connect

Multi account testing

Education

Bachelor's degree in CS/Cybersecurity

Tools

Burp Suite Pro

SoapUI

Nmap

Amass

Job description

You are an experienced offensive security professional with strong manual penetration testing expertise and a disciplined approach to testing production environments. You validate vulnerabilities through controlled exploitation attempts and produce clear, reproducible evidence.

You are comfortable testing web applications, REST/SOAP APIs, and applications protected by enterprise SSO. You understand how to assess authorization across roles and accounts, identify exploitable weaknesses, and explain their impact.

Note: This role operates under a contractor model for an initial period of 2 months, with the possibility of extension.

You Bring to Applaudo the Following Competencies:

• Bachelor’s Degree in Computer Science, Cybersecurity, Software Engineering, or a related field is desired, or equivalent professional experience.
• 5+ years of hands on penetration testing experience, including 3+ years testing web applications and APIs in production environments.
• Manual web application penetration testing following OWASP WSTG and the OWASP Top 10.
• API security testing following the OWASP API Security Top 10, including BOLA/IDOR and broken function level authorization.
• SOAP and WSDL web service testing using Burp Suite, SoapUI or an equivalent tool.
• Burp Suite Professional as your primary tool, including extensions and custom payloads.
• Experience testing applications protected by SSO with OAuth 2.0, OpenID Connect and SAML on Microsoft Entra ID.
• Multi role and multi account authorization testing methodology.
• External reconnaissance and attack surface enumeration using Amass, subfinder, httpx, Nmap or equivalent tooling.
• Proven ability to test safely in production, applying rate control, test records and defined stop conditions.
• CVSS v3.1 scoring and regulator ready reporting supported by reproducible evidence.
• Strict adherence to rules of engagement, stopping and escalating within one hour when a stop condition is met.
• Documentation discipline that records every attempt, successful or not, so results stand up to regulatory review.
• Commitment to collecting only the minimum evidence required and masking nonpublic information in all deliverables.
• Strong spoken and written English (B2+) to document findings and weekly status reports and to join live working sessions with a U.S. based security team.

Nice to haves:

• Experience testing Java EE and JSF enterprise applications, such as loan servicing or core lending platforms.
• Experience testing ASP.NET web applications and APIs.
• Experience with Azure API Management, Application Gateway or Front Door WAF.
• Experience testing payment, e signature and webhook or callback integrations.
• Python or Bash scripting to automate test cases.
• Prior participation in regulatory penetration tests under NYDFS Part 500, PCI DSS 11.4 or FFIEC.
• Offensive security certification such as OSCP, OSWE, GWAPT, GPEN, GXPN or BSCP.

You Will Be Accountable for the Following Responsibilities:

• Perform outside unauthenticated testing of in scope web applications, REST and SOAP APIs, an API gateway and internet exposed hosts.
• Perform inside testing from client provided accounts, covering cross role and cross account authorization, privilege escalation and access beyond the assigned role.
• Discover API specifications such as OpenAPI, WSDL and Postman collections for REST and SOAP services before testing when required.
• Base every finding on an exploitation attempt and record its result, listing scan only items separately as untested.
• Test all authorized in scope assets, or document the reason for exclusion when client side dependencies are not met.
• Execute all testing without causing service disruption or data loss, escalating stop conditions within one hour.
• Score findings using CVSS v3.1 and document reproducible evidence suitable for regulatory review.
• Contribute to the draft report, the final report and the signed attestation letter covering the outside, inside application and inside identity perspectives.
• Support the revalidation report delivered within 60 days of the final report.
• Report weekly status in English and participate in working sessions with the client security team.

Qualifications

• 5+ years of hands on penetration testing, including 3+ years on web applications and APIs in production.
• Manual testing aligned to OWASP WSTG, OWASP Top 10 and OWASP API Security Top 10.
• Burp Suite Professional expertise, including SOAP and WSDL service testing.
• Authorization testing across multiple roles and accounts in SSO protected applications (Entra ID, OAuth 2.0, OIDC, SAML).

Additional Information

About Us

We Are Engineered Different.

At Applaudo, talented people design, build, and scale meaningful, AI-powered solutions that create real business impact. As an AI-native organization, we collaborate across design, development, cloud, data, and artificial intelligence to turn ideas into scalable products that transform how companies operate, make decisions, and grow.

We are building a high-performance culture grounded in five values: Empowering Excellence, Collaborative Teamwork, Unsolicited Respect, Consistent Transparency, and Efficient Communication. These define how we work, how we support one another, and how we hold ourselves accountable.

Applaudo is a place for people who want to learn fast, take ownership, and work alongside strong teams they are proud to belong to. Joining us means being part of an organization that is evolving intentionally, investing in modern ways of working, and leading AI-native transformation at scale.