Samsung S10+/S9 kernel 4.14 (Android 10) Kernel Function Address (.text) and Heap Address Information Leak
An article about an info-leak in the ptrace subsystem. The bug was fixed upstream two years ago, but it still affects some Red Hat and Samsung kernels, as those didn't backport the fix.
An article about an info-leak in the ptrace subsystem. The bug was fixed upstream two years ago, but it still affects some Red Hat and Samsung kernels, as those didn't backport the fix.
SSD Secure Disclosure
SSD Advisory – Samsung S10+/S9 kernel 4.14 (Android 10) Kernel Function Address (.text) and Heap Address Information Leak - SSD…
Find out how a vulnerability discovered in Samsung S10+/S9 kernel allows leaking of sensitive function address information.
Improving the exploit for CVE-2021-26708 in the Linux kernel to bypass LKRG
I improved my PoC exploit for CVE-2021-26708, added a full-power ROP chain, and implemented a new method of bypassing the Linux Kernel Runtime Guard (LKRG).
Article: https://a13xp0p0v.github.io/2021/08/25/lkrg-bypass.html
Slides for ZeroNights conference: https://a13xp0p0v.github.io/img/CVE-2021-26708_LKRG_bypass.pdf
I improved my PoC exploit for CVE-2021-26708, added a full-power ROP chain, and implemented a new method of bypassing the Linux Kernel Runtime Guard (LKRG).
Article: https://a13xp0p0v.github.io/2021/08/25/lkrg-bypass.html
Slides for ZeroNights conference: https://a13xp0p0v.github.io/img/CVE-2021-26708_LKRG_bypass.pdf
Alexander Popov
Improving the exploit for CVE-2021-26708 in the Linux kernel to bypass LKRG
This is the follow-up to my research described in the article "Four Bytes of Power: Exploiting CVE-2021-26708 in the Linux kernel." My PoC exploit for CVE-2021-26708 had a very limited facility for privilege escalation, and I decided to continue my experiments…
The Art of Exploiting UAF by Ret2bpf in Android Kernel by Xingyu Jin and Richard Neal
Slides for the talk about exploiting an Android kernel UAF bug (CVE-2021-0399) through ret2bpf.
https://conference.hitb.org/hitbsecconf2021sin/materials/D1T1%20-%20%20The%20Art%20of%20Exploiting%20UAF%20by%20Ret2bpf%20in%20Android%20Kernel%20-%20Xingyu%20Jin%20&%20Richard%20Neal.pdf
Slides for the talk about exploiting an Android kernel UAF bug (CVE-2021-0399) through ret2bpf.
https://conference.hitb.org/hitbsecconf2021sin/materials/D1T1%20-%20%20The%20Art%20of%20Exploiting%20UAF%20by%20Ret2bpf%20in%20Android%20Kernel%20-%20Xingyu%20Jin%20&%20Richard%20Neal.pdf
Linux Kernel Security
The Art of Exploiting UAF by Ret2bpf in Android Kernel by Xingyu Jin and Richard Neal Slides for the talk about exploiting an Android kernel UAF bug (CVE-2021-0399) through ret2bpf. https://conference.hitb.org/hitbsecconf2021sin/materials/D1T1%20-%20%20…
YouTube
#HITB2021SIN D1T1 - Exploiting UAF By Ret2bpf In Android Kernel - Xingyu Jin & Richard Neal
In early 2021, an external researcher reported to Google three lines of code indicating the xt_qtaguid kernel module, used for monitoring network socket status, had a Use-After-Free vulnerability (CVE-2021-0399) for 10 years. Unfortunately, the researcher…
Solving the Kernote CTF task from 0CTF/TCTF Final 2021 by Matteo Rizzo
Nice writeup about exploiting UAF in the Linux kernel and using pt_regs for the ROP chain.
https://org.anize.rs/0CTF-2021-finals/pwn/kernote
Nice writeup about exploiting UAF in the Linux kernel and using pt_regs for the ROP chain.
https://org.anize.rs/0CTF-2021-finals/pwn/kernote
Organisers
CTF Team
Mitigating Linux kernel memory corruptions with Arm Memory Tagging
Memory tagging is coming to kill all of your favorite Linux kernel exploits.
I'll be premiering my "Mitigating Linux kernel memory corruptions with Arm Memory Tagging" LSS talk on YouTube in 24 hours. Please join in! I'll be in the YouTube chat during the talk to answer questions.
https://www.youtube.com/watch?v=UwMt0e_dC_Q
Memory tagging is coming to kill all of your favorite Linux kernel exploits.
I'll be premiering my "Mitigating Linux kernel memory corruptions with Arm Memory Tagging" LSS talk on YouTube in 24 hours. Please join in! I'll be in the YouTube chat during the talk to answer questions.
https://www.youtube.com/watch?v=UwMt0e_dC_Q
YouTube
Mitigating Linux kernel memory corruptions with Arm Memory Tagging | Linux Security Summit 2021
Memory tagging is coming to kill all of your favorite Linux kernel exploits!
Memory Tagging Extension (MTE) is an ARM v8.5 feature that enables hardware-assisted validation of the correctness of memory accesses. In a nutshell, MTE allows assigning tags to…
Memory Tagging Extension (MTE) is an ARM v8.5 feature that enables hardware-assisted validation of the correctness of memory accesses. In a nutshell, MTE allows assigning tags to…
Linux Kernel Security
Mitigating Linux kernel memory corruptions with Arm Memory Tagging Memory tagging is coming to kill all of your favorite Linux kernel exploits. I'll be premiering my "Mitigating Linux kernel memory corruptions with Arm Memory Tagging" LSS talk on YouTube…
The video is now public. The slides are here.
Google Docs
2021, Linux Security Summit: Mitigating Linux kernel memory corruptions with Arm Memory Tagging
Memory Tagging + Linux kernel = or Mitigating Linux kernel memory corruptions with Arm Memory Tagging Andrey Konovalov, xairy.io Linux Security Summit October 1st 2021
Linux Plumbers 2021
A few security-related talks from the Linux Plumbers conference this year:
- Detecting semantic bugs using differential fuzzing by Mara Mihali [video] [slides]
- Compiler Features for Kernel Security by Kees Cook [slides] [video]
- Rust for Linux by Miguel Ojeda [slides] [video]
- Android drivers in Rust by Wedson Almeida Filho [slides] [video]
- A proof-carrying approach to building correct and flexible BPF verifiers by Luke Nelson [slides] [video]
And there are many generic Linux and Android kernel–related talks, see the schedule and YouTube.
A few security-related talks from the Linux Plumbers conference this year:
- Detecting semantic bugs using differential fuzzing by Mara Mihali [video] [slides]
- Compiler Features for Kernel Security by Kees Cook [slides] [video]
- Rust for Linux by Miguel Ojeda [slides] [video]
- Android drivers in Rust by Wedson Almeida Filho [slides] [video]
- A proof-carrying approach to building correct and flexible BPF verifiers by Luke Nelson [slides] [video]
And there are many generic Linux and Android kernel–related talks, see the schedule and YouTube.
Indico
Linux Plumbers Conference 2021
20-24 September,Virtually The Linux Plumbers Conference is the premier event for developers working at all levels of the plumbing layer and beyond. LPC 2021 will be held virtually (like in 2020). We are looking forward to seeing you online!
pkill_on_warn
I've got an idea that can improve the Linux kernel security and safety. It's inspired by the exploit dev practice.
See my patch introducing pkill_on_warn: https://lore.kernel.org/linux-doc/20210929185823.499268-1-alex.popov@linux.com/T/#u
It provoked an interesting discussion with the Linux kernel rockstars, including Linus.
I've got an idea that can improve the Linux kernel security and safety. It's inspired by the exploit dev practice.
See my patch introducing pkill_on_warn: https://lore.kernel.org/linux-doc/20210929185823.499268-1-alex.popov@linux.com/T/#u
It provoked an interesting discussion with the Linux kernel rockstars, including Linus.
An eBPF fuzzer
A proof-of-concept fuzzer targeting bugs in eBPF JIT. Implemented by zerons. Inspired by a related article by Simon Scannell.
A proof-of-concept fuzzer targeting bugs in eBPF JIT. Implemented by zerons. Inspired by a related article by Simon Scannell.
GitHub
GitHub - snorez/ebpf-fuzzer: fuzz the linux kernel bpf verifier
fuzz the linux kernel bpf verifier. Contribute to snorez/ebpf-fuzzer development by creating an account on GitHub.
How a simple Linux kernel memory corruption bug can lead to complete system compromise
An article by Jann Horn describing an exploit for a locking bug leading to a corrupted reference counter in the TTY subsystem. The article also thoroughly discusses ways to mitigate memory corruption bugs.
The exploit frees a buggy slab object leaving a dangling reference to it, flushes out the page with the object to page allocator, reallocates that page and fills it with a page table, and then corrupts it via the dangling reference to gain write access to the text segment of a setuid binary.
An article by Jann Horn describing an exploit for a locking bug leading to a corrupted reference counter in the TTY subsystem. The article also thoroughly discusses ways to mitigate memory corruption bugs.
The exploit frees a buggy slab object leaving a dangling reference to it, flushes out the page with the object to page allocator, reallocates that page and fills it with a page table, and then corrupts it via the dangling reference to gain write access to the text segment of a setuid binary.
Blogspot
How a simple Linux kernel memory corruption bug can lead to complete system compromise
An analysis of current and potential kernel security mitigations Posted by Jann Horn, Project Zero Introduction This blog post de...
SuDump: Exploiting suid binaries through the kernel
An article by Itai Greenhut covering a logical bug in the Linux kernel coredump generation code.
The researchers failed to find a way to exploit the bug in default distro configurations, but they showed how to gain root privileges on Ubuntu when a user is allowed to run at least one binary as root through sudo.
Exciting to see a logical bug as a change from all those countless memory corruptions.
An article by Itai Greenhut covering a logical bug in the Linux kernel coredump generation code.
The researchers failed to find a way to exploit the bug in default distro configurations, but they showed how to gain root privileges on Ubuntu when a user is allowed to run at least one binary as root through sudo.
Exciting to see a logical bug as a change from all those countless memory corruptions.
Alephsecurity
SuDump: Exploiting suid binaries through the kernel
Virtio snapshotting with KVM VMI for fuzzing
Tamas Lengyel posted the instructions for fuzzing KVM/virtio snapshots on Xen:
https://github.com/intel/kernel-fuzzer-for-xen-project/wiki/Virtio-snapshotting-with-KVM-VMI
Tamas Lengyel posted the instructions for fuzzing KVM/virtio snapshots on Xen:
https://github.com/intel/kernel-fuzzer-for-xen-project/wiki/Virtio-snapshotting-with-KVM-VMI
GitHub
Virtio snapshotting with KVM VMI
Kernel Fuzzer for Xen Project (KF/x) - Hypervisor-based fuzzing using Xen VM forking, VMI & AFL - Virtio snapshotting with KVM VMI · intel/kernel-fuzzer-for-xen-project Wiki
Blue Klotski (CVE-2021-3573) and the story for fixing
An article by f0rm2l1n about an LPE exploit for a use-after-free bug in the Bluetooth stack. Triggering requires CAP_NET_ADMIN.
An article by f0rm2l1n about an LPE exploit for a use-after-free bug in the Bluetooth stack. Triggering requires CAP_NET_ADMIN.
CVE-2021-43267: Remote Linux Kernel Heap Overflow | TIPC Module Allows Arbitrary Code Execution
An article about a remotely-triggerable slab-buffer-overflow in the packet parsing paths for the TIPC protocol. By Max Van Amerongen.
The bug was found with CodeQL. Neither a remote nor a local exploit is provided. The TIPC module needs to be loaded manually for the bug to be triggerable.
An article about a remotely-triggerable slab-buffer-overflow in the packet parsing paths for the TIPC protocol. By Max Van Amerongen.
The bug was found with CodeQL. Neither a remote nor a local exploit is provided. The TIPC module needs to be loaded manually for the bug to be triggerable.
SentinelOne
CVE-2021-43267: Remote Linux Kernel Heap Overflow | TIPC Module Allows Arbitrary Code Execution
SentinelLabs has discovered a heap overflow vulnerability in the TIPC module of the Linux Kernel which can allow attackers to compromise an entire system.
CVE-2021-34866 Writeup
An article covering exploitation of a type confusion in the eBPF subsystem. By HexRabbit. Written in Chinese.
The exploit requires having CAP_BPF (or CAP_SYS_ADMIN on older systems) in the root user namespace.
An article covering exploitation of a type confusion in the eBPF subsystem. By HexRabbit. Written in Chinese.
The exploit requires having CAP_BPF (or CAP_SYS_ADMIN on older systems) in the root user namespace.
HexRabbit's Blog
CVE-2021-34866 Writeup - HexRabbit's Blog
CVE-2021-34866 Writeup幾天前在 Twitter 上看到 @flatt_secu
Linux Security Summit 2021
Talks on Linux kernel security:
— CVEHound: Audit Kernel Sources for Missing CVE Fixes by Denis Efremov [slides] [video]: A tool to detect missing CVE fixes in given kernel sources based on manually-written Coccinelle rules; covers 300 CVEs at the moment.
— Kernel Self-Protection Project by Kees Cook [slides] [video]: New security features in kernel versions 5.3–5.16.
— Triaging Kernel Out-Of-Bounds Write Vulnerabilities by Weiteng Chen [slides] [video]: Automating exploitation of out-of-bounds bugs to achieve IP-hijacking.
— Revealing High-Risk Security Impacts of Fuzzer-Exposed Bugs in Linux kernel by Xiaochen Zou [slides] [video] [LWN writeup]: Assessing security impact of Syzkaller-found bugs via symbolic execution.
— Finding Multiple Bug Effects for More Precise Exploitability Estimation by Zhenpeng Lin and Yueqi Chen [slides] [video]: Assessing security impact of Syzkaller-found bugs via targeted fuzzing.
And the already mentioned:
— Mitigating Linux Kernel Memory Corruptions with ARM Memory Tagging by Andrey Konovalov [slides] [video]: Using Arm Memory Tagging to protect the kernel against memory corruptions exploits.
Talks on Linux kernel security:
— CVEHound: Audit Kernel Sources for Missing CVE Fixes by Denis Efremov [slides] [video]: A tool to detect missing CVE fixes in given kernel sources based on manually-written Coccinelle rules; covers 300 CVEs at the moment.
— Kernel Self-Protection Project by Kees Cook [slides] [video]: New security features in kernel versions 5.3–5.16.
— Triaging Kernel Out-Of-Bounds Write Vulnerabilities by Weiteng Chen [slides] [video]: Automating exploitation of out-of-bounds bugs to achieve IP-hijacking.
— Revealing High-Risk Security Impacts of Fuzzer-Exposed Bugs in Linux kernel by Xiaochen Zou [slides] [video] [LWN writeup]: Assessing security impact of Syzkaller-found bugs via symbolic execution.
— Finding Multiple Bug Effects for More Precise Exploitability Estimation by Zhenpeng Lin and Yueqi Chen [slides] [video]: Assessing security impact of Syzkaller-found bugs via targeted fuzzing.
And the already mentioned:
— Mitigating Linux Kernel Memory Corruptions with ARM Memory Tagging by Andrey Konovalov [slides] [video]: Using Arm Memory Tagging to protect the kernel against memory corruptions exploits.
Achieving Linux Kernel Code Execution Through a Malicious USB Device
A Black Hat Europe 2021 talk about exploiting a double-free in the USB MIDI driver over USB. The exploit works against devices with writable code section. By Martijn Bogaard and Dana Geist.
This is the first Linux-kernel-host-code-execution-over-USB exploit known to me.
The exploit is based on the bug I found a few years ago. However, my exploit required cooperating userspace, so it didn't really count. Happy to see a purely USB one!
Exploiting a USB host from the device side is hard due to limited control: the device can only respond to host's requests. You can't simply start sending messages for heap shaping, etc. You need to find a way to make the kernel ask for those.
A Black Hat Europe 2021 talk about exploiting a double-free in the USB MIDI driver over USB. The exploit works against devices with writable code section. By Martijn Bogaard and Dana Geist.
This is the first Linux-kernel-host-code-execution-over-USB exploit known to me.
The exploit is based on the bug I found a few years ago. However, my exploit required cooperating userspace, so it didn't really count. Happy to see a purely USB one!
Exploiting a USB host from the device side is hard due to limited control: the device can only respond to host's requests. You can't simply start sending messages for heap shaping, etc. You need to find a way to make the kernel ask for those.
SLUB overflow CVE-2021-42327
A concise article about exploiting a slab buffer-overflow bug in the AMD GPU driver. By Thelford Williams.
The author didn't have access to an AMD GPU, so they manually replicated the vulnerable code. The exploit uses msg_msg elastic objects to leak the kernel address, overwrite slab freelist pointer, allocate memory containing modprobe_path, and overwrite it for code execution.
A concise article about exploiting a slab buffer-overflow bug in the AMD GPU driver. By Thelford Williams.
The author didn't have access to an AMD GPU, so they manually replicated the vulnerable code. The exploit uses msg_msg elastic objects to leak the kernel address, overwrite slab freelist pointer, allocate memory containing modprobe_path, and overwrite it for code execution.
The blog
CVE-2021-42327 GPU kernel driver SLUB overflow
Introduction