Allele Security Intelligence

Nossas recentes contribuições para o kernel do Linux

Posted on October 20, 2025 by Allele Security Intelligence in Pesquisa

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Durante nossos projetos de pesquisa, precisamos investigar profundamente os subsistemas dos sistemas operacionais que são nosso alvo. Nesse processo, frequentemente encontramos outros problemas que não se alinham diretamente com nossos objetivos de pesquisa. No passado, nós os ignorávamos, mas recentemente decidimos iniciar um ciclo de contribuição, reportando e corrigindo essas falhas.

Especificamente para os problemas abordados nesta postagem, nós não apenas os reportamos, como também submetemos os patches de correção. Embora já tenhamos reportado vulnerabilidades e auxiliado em suas correções no passado, estes problemas marcam as primeiras instâncias em que somos os únicos autores dos patches submetidos.

Nesta postagem, detalhamos os problemas que reportamos e corrigimos no kernel do Linux.

Dos três itens reportados, dois são NULL pointer dereferences e o terceiro é um potencial out-of-bounds write no subsistema de arquivos Btrfs. Os NULL pointer dereferences poderiam permitir que usuários não privilegiados afetassem o funcionamento do sistema. Não investimos tempo significativo para tentar acionar a vulnerabilidade potencial de out-of-bounds no Btrfs, pois ela não era prioritária para nossos objetivos de pesquisa.

Embora a vulnerabilidade exista, ela requer uma condição que não parece trivial de ser alcançada. O mais notável sobre essa vulnerabilidade em particular é que ela é extremamente antiga, estando presente no kernel do Linux por mais de 17 anos. Ela havia sido identificada e houve uma tentativa de correção no passado, mas essa falha foi posteriormente esquecida. Apesar de o código vulnerável ter sido modificado diversas vezes desde a tentativa de correção original, a vulnerabilidade persistiu.

Todos os patches que submetemos já foram aplicados no upstream do kernel. A seguir, você encontrará todos os detalhes técnicos sobre cada uma das correções.

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Our recent contributions to the Linux kernel

Posted on October 20, 2025August 17, 2026 by Allele Security Intelligence in Research

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During our research projects, we need to delve deep into the target operating system’s subsystems. In the process, we often find issues that are not interesting for our research purposes. In the past, we ignored them, but recently we have decided to contribute back to the upstream community by reporting these issues. In the cases covered by this blog post, we not only reported the issues but also submitted the corresponding patches. Even though we have reported vulnerabilities and helped to fix them in the past, these issues are the first for which we were the sole patch authors. In this blog post, we will detail the recent issues we have reported and fixed in the Linux kernel.

We reported three issues. Two of them are NULL pointer dereferences, and the third is a potential out-of-bounds write in the Btrfs file system. The NULL pointer dereference issues could allow unprivileged users to disrupt the system. We did not invest much time trying to trigger the potential out-of-bounds write in Btrfs, as it falls outside our research scope.

Although the vulnerability exists, it requires a condition that does not appear trivial to meet. The most interesting thing about it is that it is an “ancient” bug. The buggy code has been there for more than 17 years. While it was noticed in the past and an attempt was made to fix it, that effort was overlooked. Despite the vulnerable code having been touched several times since then, the vulnerability remained present. All of the patches are already applied upstream, and now we will detail the issues.

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Conheça o Portfólio de Serviços da Allele Security Intelligence

Posted on September 17, 2025August 21, 2026 by Allele Security Intelligence in Institucional

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Na Allele Security Intelligence, entendemos que a resiliência cibernética é um fator crítico para a continuidade e competitividade das organizações. Nosso compromisso é apoiar empresas na gestão proativa de riscos digitais, fornecendo soluções integradas, constantemente atualizadas e alinhadas às exigências regulatórias e aos cenários reais de ameaça. Atuamos de forma estratégica, combinando inovação, inteligência de ameaças e expertise técnica avançada, para que nossos clientes possam antecipar, detectar e responder de maneira eficaz aos desafios cada vez mais complexos da cibersegurança.

Nosso Portfólio de Cibersegurança reúne serviços projetados a partir de pesquisa aplicada de ponta, sustentados por excelência técnica e consolidados por experiência prática em ambientes complexos.

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Discover the Allele Security Intelligence Services Portfolio

Posted on September 17, 2025August 21, 2026 by Allele Security Intelligence in Institutional

Para acessar esta postagem em português, clique aqui.

At Allele Security Intelligence, we understand that cyber resilience is a critical factor for the continuity and competitiveness of organizations. Our commitment is to support companies in the proactive management of digital risks, providing integrated solutions that are constantly updated and aligned with regulatory requirements and real-world threat scenarios.

We operate strategically, combining innovation, threat intelligence, and advanced technical expertise, so that our clients can anticipate, detect, and effectively respond to the increasingly complex cybersecurity challenges.

Our Cybersecurity Portfolio brings together services designed from cutting-edge applied research, sustained by technical excellence, and consolidated by practical experience in complex environments.

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Use-after-free vulnerability in the CAN BCM subsystem leading to information disclosure (CVE-2023-52922)

Posted on June 9, 2025August 21, 2026 by Allele Security Intelligence in Research

Para acessar esta postagem em português, clique aqui.

In 2024, our research team noticed and wrote proofs of concept for a use-after-free vulnerability affecting the latest Red Hat Enterprise Linux 9 (RHEL 9). At the time, kernel version 5.14.0-503.15.1.el9_5. The vulnerability was fixed in the Linux kernel upstream on July 17, 2023 [1][2]. After we reported it, the fix was backported to Red Hat Enterprise Linux 9 on March 11, 2025 [3], in the kernel version 5.14.0-503.31.1.el9_5.

We reported it to Red Hat on July 16, 2024, and they replied that upstream declined to issue a CVE and asked us for the proof of concept we had mentioned during the first contact. After sending a detailed report including a proof of concept, the CVE-2023-52922 [4] was assigned. This blog post also highlights a potential pattern that has been present in the CAN BCM subsystem, as at least another issue has already been reported and fixed.

This vulnerability allows unprivileged users to read data from kernel space, which could be used to disclose sensitive information and bypass security mitigations enabled by default in the affected systems.

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Accidentally uncovering a seven years old vulnerability in the Linux kernel

Posted on February 5, 2025August 21, 2026 by Allele Security Intelligence in Research

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Vulnerability research is at the core of Allele Security Intelligence. We have been actively researching for more than a decade, and we offer our expertise to our clients. Among the services we offer are 0day and nday vulnerability research.

In nday vulnerability research projects, in the case of the Linux kernel, we look for vulnerabilities patched upstream, that still affect major distributions even in their latest release. Usually, we find vulnerabilities patched over a year ago that still affect popular Linux distributions. We do that by auditing the Linux kernel source code, monitoring vulnerabilities submitted to mailing lists and patched upstream, checking the findings of the syzkaller fuzzer and other ways.

While doing that research, we accidentally discovered a vulnerability in the core of the TCP subsystem of the Linux kernel. It had been introduced seven years earlier. We reported it upstream, which was patched in May of last year. In this blog post, we’ll share how it happened and briefly analyze the vulnerability.

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10º Edição da Null Byte Security Conference

Posted on December 23, 2024August 21, 2026 by Allele Security Intelligence in Eventos

No final de Novembro, há algumas semanas, aconteceu a 10º Edição da Null Byte Security Conference em Salvador, Bahia. Nosso time estava presente e nosso diretor e principal pesquisador Anderson Nascimento palestrou sobre “A importância de uma metodologia rigorosa em pesquisa em segurança da informação”. Os slides podem ser encontrados aqui.

A apresentação teve como objetivo demonstrar a importância da utilização de uma metodologia rigorosa em trabalhos e pesquisas de segurança da informação. Ao utilizá-la, podemos detectar erros e vieses que podem influenciar o resultado, invalidando-os ou levando a falsos positivos. Metodologia é muito importante na Allele Security Intelligence, pois com o rigor metodológico oferecemos aos nossos clientes um nível elevado de qualidade em nossos serviços, da consultoria à pesquisas.

Essa edição da Null Byte Security Conference foi especial. São 10 anos de uma conferência em segurança da informação em Salvador, cidade onde a Allele Security Intelligence surgiu, e por este motivo não poderíamos estar de fora. Além disso, a Null Byte se destaca entre as principais conferências de segurança da informação do país, sempre com excelentes palestras técnicas e reunindo grandes nomes da área de segurança da informação do país.

The solution to keep your systems secure: Kernel Livepatch

Posted on December 6, 2024August 21, 2026 by Allele Security Intelligence in Consulting

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Keeping systems up-to-date with the latest vulnerability patches is crucial for organizational security. New vulnerabilities are frequently discovered, increasing exposure to attacks. However, regarding a system’s main component—the kernel—such updates typically require a complete system reboot, which can reduce server uptime and potentially affect service quality. Additionally, in a kernel update provided by the vendor, there are often other modifications beyond vulnerability patches, which can alter system behavior unexpectedly. Fortunately, there is a technique for patching kernel vulnerabilities that avoids these negative impacts.

Linux Livepatch is the solution. This feature allows you to apply security updates and critical patches without rebooting or interrupting services. This makes your systems more secure and highly available 24/7, reducing risks and maximizing productivity. It also enables patching vulnerabilities unknown to the public and vendors, like vulnerabilities discovered by our research team. Next, we will provide further details to help you understand this solution.

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