CVE-2021-3490 – Pwning Linux kernel eBPF on Ubuntu machines

Researcher published an exploit code for a high-severity privilege escalation flaw (CVE-2021-3490) in Linux kernel eBPF on Ubuntu machines.

The security researcher Manfred Paul of the RedRocket CTF team released the exploit code for a high-severity privilege escalation bug, tracked as CVE-2021-3490, in Linux kernel eBPF (Extended Berkeley Packet Filter). A local attacker could exploit the flaw to escalate privileges on Ubuntu machines.

Extended Berkeley Packet Filter (eBPF) is a kernel technology (starting in Linux 4.x) that allows programs to run without having to change the kernel source code or adding additional modules. It is a sort of lightweight, sandbox virtual machine (VM) inside the Linux kernel, where programmers can run BPF bytecode that takes advantage of specific kernel resources.

Paul reported the bug in May through Trend Micro’s Zero Day Initiative, he demonstrated that user-supplied programs are not properly validated before being executed.

The security researcher Valentina Palmiotti published a blog post that contains technical details about the flaw along with the exploit code that works on fresh installs of both Ubuntu 20.10 and 21.04

She demonstrates how to exploit the issue to trigger a DoS condition of escalate privileges.

Below is a video PoC for the CVE-2021-3490 vulnerability on Ubuntu 21.04 published by the researcher:

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Pierluigi Paganini

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(SecurityAffairs – hacking, Linux)

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Pierluigi Paganini

Pierluigi Paganini is member of the ENISA (European Union Agency for Network and Information Security) Threat Landscape Stakeholder Group and Cyber G7 Group, he is also a Security Evangelist, Security Analyst and Freelance Writer. Editor-in-Chief at "Cyber Defense Magazine", Pierluigi is a cyber security expert with over 20 years experience in the field, he is Certified Ethical Hacker at EC Council in London. The passion for writing and a strong belief that security is founded on sharing and awareness led Pierluigi to find the security blog "Security Affairs" recently named a Top National Security Resource for US. Pierluigi is a member of the "The Hacker News" team and he is a writer for some major publications in the field such as Cyber War Zone, ICTTF, Infosec Island, Infosec Institute, The Hacker News Magazine and for many other Security magazines. Author of the Books "The Deep Dark Web" and “Digital Virtual Currency and Bitcoin”.