LESIS Bulletin #7 - CTF victory, open-source security and community

Introduction

This month, we highlight an open-source tool developed by LESIS, celebrate the GRIS/UFRJ team's first-place finish at the SBSeg CTF, and share our upcoming participation in Mind The Sec and sponsorship of BSides CWB. From practical security research to technical challenges and community initiatives, this edition brings together projects and events that contribute to the development and exchange of cybersecurity knowledge.

Highlight

GRIS/UFRJ takes first place at the SBSeg CTF

On August 29, 2026, the GRIS/UFRJ team, supported by LESIS, won 1st place among 18 teams at the Capture The Flag competition held as part of the 26th Brazilian Cybersecurity Symposium (SBSeg 2026). The team finished with 6,765 points, maintaining the lead throughout the eight-hour competition.

Inspired by the FIRST CTF, the event focused on defensive security, challenging participants to analyze network traffic, forensic artifacts, cryptography, incident response, and other technical evidence.

Congratulations to Rafael Mello, Pedro Kitagawa, Abid Lohan, and Guilherme Sobreira on this achievement. LESIS is proud to support the team and initiatives that strengthen technical development and knowledge sharing within the cybersecurity community.

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Tool Spotlight

Perceptio — Multilingual sentiment analysis from the command line

Perceptio is an open-source, lexicon-based framework developed by LESIS for analyzing the emotional sentiment of textual data. It provides a command-line interface that measures sentiment using words and their associated emotional scores, offering a transparent and extensible approach to text analysis.

The tool supports multiple languages, automatic language detection, and analysis of complete documents or individual sentences. It accepts text directly or from files and can produce results in plain text or JSON, making it suitable for both interactive use and integration into scripts and broader research workflows.

Perceptio also includes resource-generation capabilities for translating lexicons and abbreviation lists into additional languages through the Google Cloud Translation API. This allows researchers and developers to extend the framework to different linguistic contexts and experiment with multilingual sentiment analysis.

The project is written in Perl, distributed under the MIT License, and available for use and contribution.

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Community

LESIS at Mind The Sec 2026

LESIS will be attending Mind The Sec 2026 as a participant, joining cybersecurity professionals, researchers, and industry leaders in São Paulo from September 15 to 17.

The event brings together the information security community to discuss emerging threats, security strategies, technological developments, and the challenges facing organizations and professionals across the industry.

Participating in Mind The Sec is an opportunity for LESIS to follow current discussions, exchange perspectives with professionals from different areas, and strengthen connections within the cybersecurity ecosystem. We look forward to attending the sessions, meeting members of the community, and bringing new insights into our research and technical work.

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LESIS sponsors BSides CWB 2026

LESIS is proud to sponsor BSides CWB 2026, supporting an event built by and for the cybersecurity community.

The first official edition of BSides Curitiba will take place on October 17, 2026, at PUCPR in Curitiba, bringing together professionals, researchers, students, and enthusiasts for a full day of talks, workshops, CTF challenges, villages, and community exchange.

Supporting initiatives like BSides CWB reflects our commitment to strengthening spaces where technical knowledge can be shared openly and where new connections, ideas, and research can emerge.

Free tickets are available through the event website, alongside a supporter ticket option. If you are planning to attend, you can already secure your spot.

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Closing

LESIS is an applied security research entity focused on developing effective offensive technologies in support of critical operations. Its approach is grounded in a thorough attacker’s perspective and rigorous, research-driven thinking

If you found this issue interesting, feel free to share it with colleagues working in security research.
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