In our previous article Yet another bug into Netfilter, I presented a vulnerability found within the netfilter subsystem of the Linux kernel. During my investigation, I found a weird comparison that does not fully protect a copy within a buffer. It led to a heap buffer overflow that was exploited to obtain root privileges on Ubuntu 22.04.

Open-source code runs on every computer on the planet—and keeps America’s critical infrastructure going. DARPA is worried about how well it can be trusted

Introduction Rootkits are dangerous pieces of malware. Once in place, they are usually really hard to detect. Their code is typically more challenging to write than other malware, so developers resort to code reuse from open source projects. As rootkits are very interesting to analyze, we are always looking out for these kinds of samples […]

Symbiote is a new Linux malware we discovered that acts in a parasitic nature, infecting other running processes to inflict damage on machines.

At Grapl we believe that in order to build the best defensive system we need to deeply understand attacker behaviors. As part of that goal we're investing in offensive security research. Keep up with our blog for new research on high risk vulnerabilities, exploitation, and advanced threat tactics.

Trend Micro Research detected “Cheerscrypt”, a new Linux-based ransomware variant that compromises ESXi servers. We discuss our initial findings in this report.

Observing a 254% increase in activity over the last six months from a versatile Linux trojan called XorDdos, the Microsoft 365 Defender research team provides in-depth analysis into this stealthy malware's capabilities and key infection signs.

Yet another malicious Python package has been spotted in the PyPI registry performing supply chain attacks to drop Cobalt Strike beacons and backdoors on Windows, Linux, and macOS systems.

Microsoft has discovered several vulnerabilities, collectively referred to as Nimbuspwn, that could be chained together, allowing an attacker to elevate privileges to root on many Linux desktop endpoints. Leveraging Nimbuspwn as a vector for root access could allow attackers to achieve greater impact on vulnerable devices by deploying payloads and performing other malicious actions via arbitrary root code execution.

A few weeks ago, I found and reported CVE-2022-25636 - a heap out of bounds write in the Linux kernel. The bug is exploitable to achieve kernel code execution (via ROP), giving full local privilege escalation, container escape, whatever you want.

This is the story of CVE-2022-0847, a vulnerability in the Linux kernel since 5.8 which allows overwriting data in arbitrary read-only files. This leads to privilege escalation because unprivileged processes can inject code into root processes. It is similar to CVE-2016-5195 “Dirty Cow” but is easier to exploit. The vulnerability was fixed in Linux 5.16.11, 5.15.25 and 5.10.102.

On Feb. 4, Linux announced CVE-2022-0492, a new privilege escalation vulnerability in the kernel. CVE-2022-0492 marks a logical bug in control groups (cgroups), a Linux feature that is a fundamental building block of containers. The issue stands out as one of the simplest Linux privilege escalations discovered in recent times: The Linux kernel mistakenly exposed a privileged operation to unprivileged users.

Découverte dans le gestionnaire de paquets Snap pour systèmes Linux développé par Canonical, une faille expose les utilisateurs à de l'escalade de privilèges. Un risque qui peut déboucher jusqu'à de l'accès root.

CrowdStrike has observed that malware targeting Linux-based systems increased by 35% in 2021. XorDDoS, Mirai and Mozi were the most common malware families.

Un inquiétant cheval de Troie très discret et multiplateformes vient d'être repéré. Baptisé SysJoker et mis en lumière par la firme de sécurité Intezer, il peut cibler autant Windows, Linux que macOS. Pire encore, celui-ci passait sous les radars des antivirus depuis un bout de temps. Les versions Linux et macOS n'étaient jusqu'à présent pas du tout détectées par des sites

In December 2021, we discovered a new multi-platform backdoor that targets Windows, Mac, and Linux that we have named SysJoker.

The Qualys Research Team has discovered a memory corruption vulnerability in polkit's pkexec, a SUID-root program that is installed by default on every major…

Netfilter is a framework in the Linux kernel for implementing various networking-related tasks with user-defined handlers. Netfilter provides various functions for packet filtering, network address translation and port translation, and packet logging. Netfilter represents a set of hooks that allow other kernel modules to register callback functions in the kernel’s networking stack.

Operating system access controls, that constrain which programs can open which files, have existed for almost as long as computers themselves. Access controls are still widely used and are more flexible and efficient when compared to cryptographically protecting files. Despite the long history, ther

This report discusses new ransomware, that targets Windows, Linux and ESXi systems: Luna written in Rust and Black Basta.

In our previous article Yet another bug into Netfilter, I presented a vulnerability found within the netfilter subsystem of the Linux kernel. During my investigation, I found a weird comparison that does not fully protect a copy within a buffer. It led to a heap buffer overflow that was exploited to obtain root privileges on Ubuntu 22.04.

Open-source code runs on every computer on the planet—and keeps America’s critical infrastructure going. DARPA is worried about how well it can be trusted

Introduction Rootkits are dangerous pieces of malware. Once in place, they are usually really hard to detect. Their code is typically more challenging to write than other malware, so developers resort to code reuse from open source projects. As rootkits are very interesting to analyze, we are always looking out for these kinds of samples […]

Symbiote is a new Linux malware we discovered that acts in a parasitic nature, infecting other running processes to inflict damage on machines.

At Grapl we believe that in order to build the best defensive system we need to deeply understand attacker behaviors. As part of that goal we're investing in offensive security research. Keep up with our blog for new research on high risk vulnerabilities, exploitation, and advanced threat tactics.

Trend Micro Research detected “Cheerscrypt”, a new Linux-based ransomware variant that compromises ESXi servers. We discuss our initial findings in this report.

Observing a 254% increase in activity over the last six months from a versatile Linux trojan called XorDdos, the Microsoft 365 Defender research team provides in-depth analysis into this stealthy malware's capabilities and key infection signs.

Yet another malicious Python package has been spotted in the PyPI registry performing supply chain attacks to drop Cobalt Strike beacons and backdoors on Windows, Linux, and macOS systems.

Microsoft has discovered several vulnerabilities, collectively referred to as Nimbuspwn, that could be chained together, allowing an attacker to elevate privileges to root on many Linux desktop endpoints. Leveraging Nimbuspwn as a vector for root access could allow attackers to achieve greater impact on vulnerable devices by deploying payloads and performing other malicious actions via arbitrary root code execution.

A few weeks ago, I found and reported CVE-2022-25636 - a heap out of bounds write in the Linux kernel. The bug is exploitable to achieve kernel code execution (via ROP), giving full local privilege escalation, container escape, whatever you want.