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.

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.

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.

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.

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.

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.