The new Dirty COW Linux Kernel Exploit already used in attacks in the wild
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2016-5195 | Dirty COW Race Condition Enables Local Privilege Escalation in the Linux Kernel CVE-2016-5195, widely known as 'Dirty COW', is a race condition (CWE-362) in the copy-on-write (COW) memory-handling code in mm/gup.c of the Linux kernel, affecting kernel versions 2.x through 4.x before 4.8.3. A local user with low privileges can trigger the race — including via the PTRACE_POKEDATA path used in public exploits — to write to a read-only memory mapping that should not be writable, corrupting files or overwriting memory. This yields root-level privileges on the host, enabling full system takeover, malware implantation and persistence. Any system running an affected kernel is exposed, spanning Ubuntu, Red Hat Enterprise Linux (including AUS, EUS, Long Life and TUS variants), Debian, Fedora, Palo Alto Networks PAN-OS, and NetApp Cloud Backup and HCI Storage Nodes that ship an affected kernel. Exploitation is confirmed in the wild: the flaw was actively exploited in October 2016, including by the first Android malware found using it to gain root, it was added to CISA's KEV catalog on 2022-03-03 with the required action to apply vendor updates, and EPSS currently assigns an 83.5% probability of exploitation in the next 30 days (100th percentile). Do: Upgrade to Linux kernel 4.8.3 or later, or apply the vendor-issued patched/backported kernel updates from Canonical, Red Hat, Debian, Fedora Project, Palo Alto Networks (PAN-OS) and NetApp, per the CISA KEV required action. Prioritize unpatched legacy servers and internet-exposed Linux hosts — especially multi-user systems, SSH-accessible machines and containers where untrusted users can run code — and update Android devices that may have been silently rooted via Dirty COW. Until patching completes, restrict local and SSH access to trusted users, since exploitation requires local low-privileged code execution. | 7.0 | 84% | KEV PoC ×5 |
| mass≈ hundreds of millions of Linux systems and devices (affected kernels shipped in nearly all mainstream distributions, appliances and Android devices of the… |
Full article395 words · extracted from securityaffairs.com · click to collapse
Experts disclosed a new Linux kernel vulnerability dubbed Dirty COW that could be exploited by an unprivileged local attacker to escalate privileges.
The security expert Phil Oester discovered in the Linux kernel a new flaw, dubbed ‘Dirty COW‘ that could be exploited by a local attacker to escalate privileges.
The name “Dirty COW” is due to the fact that it’s triggered by a race condition in the way the Linux kernel’s memory subsystem handles copy-on-write (COW) breakage of private read-only memory mappings.
According to the security advisory published by Red Had, the vulnerability, tracked as CVE-2016-5195, allows local attackers to modify existing setuid files.
“A race condition was found in the way the Linux kernel’s memory subsystem handled the copy-on-write (COW) breakage of private read-only memory mappings. An unprivileged local user could use this flaw to gain write access to otherwise read-only memory mappings and thus increase their privileges on the system.” states the Red Had security advisory.
“This could be abused by an attacker to modify existing setuid files with instructions to elevate privileges. An exploit using this technique has been found in the wild.”
Red Hat also confirmed that attackers are using an exploit leveraging the Dirty COW in the wild.
The good news is that a solution to the issue is already available and Linux distributions have started releasing updates.
There is also a curious aspect of the Dirty COW, researchers that discovered it launched a sort of marketing operation around the issue, created a website, a logo and a Twitter account. They are also running a shop that sells “Dirty COW” mugs and t-shirts.
Let me close with one of the questions in the FAQ session of the website:
Can my antivirus detect or block this attack?
“Although the attack can happen in different layers, antivirus signatures that detect Dirty COW could be developed. Due to the attack complexity, differentiating between legitimate use and attack cannot be done easily, but the attack may be detected by comparing the size of the binary against the size of the original binary. This implies that antivirus can be programmed to detect the attack but not to block it unless binaries are blocked altogether.”
The researchers also published the exploit code on GitHub.
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(Security Affairs – Linux, hacking)
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Text extracted automatically; images, tables and formatting may be missing. Original: https://securityaffairs.com/52521/hacking/dirty-cow-exploit.html