Questions tagged [kernel]
The kernel tag has no usage guidance.
138
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Kernel level attack?
In a Unix-like system, the concept of privileged and non-privileged users is used for security, preventing numerous attacks. When a non-privileged user executes malicious code at a normal level, the ...
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How does IOMMU and/or Linux kernel handle DMA that span a page boundary?
I am looking into how DMA works at the device driver and kernel level in the Linux kernel.
I observed that access control to DMA buffers from IO devices is performed by the IOMMU and IOMMU driver in ...
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Is having no driver installed better than having old driver?
How safe are installed & genuine-vendor signed old drivers, specifically when attackers are spoofing Microsoft and other vendor certificates?
On older PCs and laptops where some components are no ...
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Hooking system calls for a specific process on Linux
I want to make it so that syscalls from a particular process are controlled by another process (admin or same user, doesn't really matter to me.) I realize this gives some rootkit trojan vibes, but I'...
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OriginalFirstThunk in memory
I understand the point of IAT/IDT/ INT and dynamically loaded DLLs at runtime. The OriginalFirstThunk in the Import Directory table refers to the function names stored (in the case of an ordinal) in ...
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Linux BPFtrace - user switch from suid bit applications not detected
I want to monitor systemcalls with bpftrace (https://github.com/iovisor/bpftrace/). For most systemcalls, this works without problems, but I have problems to monitor applications, where the suid bit ...
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user namespaces: do they increase security, or introduce new attack surface?
user namespaces in Linux are presented as a security feature, which should increase security. But is this really true?
Is it possible that while user namespaces fix one kind of problem, they introduce ...
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Can I know kernel address layout and memory mapped IO layout from the user privilege in linux kernel?
My current understanding is that the user does not have any way of knowing the kernel address space layout due to the protection mechanisms such as Kernel Address Space Layout Randomization (KASLR).
...
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Why does this method of modifying kernel memory work?
I have no experience of kernel programming or anything low level. I just watched this video and at 21:10 the presenter started to talk about modifying kernel memory using two pointers.
From my ...
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Explanation of capabilities: CAP_NET_BIND_SERVICE
I am still studying kernel credential management (https://kernel.org/doc/html/v5.9/security/credentials.html) and I have encountered a use case I cannot explain.
I am in a VM (Kali).
❯ uname -a
...
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Capabilities DROP in container of Kubernetes pod running with specific UID
I am doing some security research on Kubernetes and I found something still mysterious to me, concerning capabilities.
Example of simple pod:
apiVersion: v1
kind: Pod
metadata:
name: my-pod-httpd
...
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Was the kernel I used vulnerable/deprecated?
Background Information
As I developer I am running multiple (partly virtual-)machines with Debian GNU/Linux and on some of these machines I work with highly confidential documents or dangerous ...
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Is there a difference between a bootkit and a ring-0 rootkit?
I understand the difference between a Ring-0 rootkit and a Ring-3 rootkit, in terms of their hierarchical depth in computational models. That is kernel mode and usermode, respectively.
I am confused ...
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A Continuous Flood of Kernel Warnings. Am I under attack?
I have a Linksys WRT1200AC with DD-WRT v3.0-r48865 std. It's connected to the Internet through the ISP's modem in bridge mode.
My syslog reports continuously, many times per second stuff like this:
...
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Container escape - CVE-2022-0492 - hybrid cgroups?
I saw the recent CVE-2022-0492 that can enable container escape, and I have a decent understanding of cgroups and container capabilities, but not very familiar with how hybrid cgroup v1/v2 works, nor ...
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Security of a ro volume in Docker
What are the security implications of mapping a host folder to a Docker container ro? For example -v /usr/local/bin:/usr/local/bin:ro.
Of course, the container can now read the host folder. But, ...
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How does gVisor run its own kernel replacement under Docker for security? [closed]
I learned about gVisor from https://security.stackexchange.com/a/259275/133925 . It runs containers under a custom kernel, written in Go, with very intense security.
My question is: The whole point ...
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How to execute Android verified boot during first boot after updating OS in Android?
I need to execute AVB (Android verified boot) during first boot after updating Android OS. BOARD_AVB_ENABLE = true is already present in the mk file device/hikey/common/BoardConfigCommon.mk in the ...
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How to completely restrict Steam in Linux to defend against remote zero day exploits?
My question is, how can i completely restrict Steam's processes and modules to only have access to what they suppose to, and not be able to do anything malicious, for example running bin/sh or ...
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What physical damage can a user mode windows driver do?
If a driver runs in kernel mode it obviously can manipulate everything (well everything in ring 0), so manipulating the file system or devices is a possibility. Potentially devices can be destroyed, ...
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How to go about checking if Windows is running any untrusted drivers (programatically)
I want to enforce a rule that my program start only if, at the time it launches, there are no untrusted kernel drivers running. I'm aware and have already tested file signature verification using ...
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Is Zircon kernel (from Fuchsia OS) safer by being a microkernel?
Fuchsia's possible Android replacement uses the Zircon microkernel. This means that the drivers should run in userspace.
Is this an advantage over Android? For example, closed source drivers now can't ...
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How effective is Windows KDP for exploit mitigation in practice?
Windows Kernel Data Protection is a kernel security feature which appears to use Extended Page Tables (EPT, a hardware virtualization feature) to enforce read-only pages. How effective is this at ...
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How to detect fileless kernel compromise in linux
Is there a way to detect fileless kernel compromise in Linux?
The only one way to analyze this kind of attack is by volatility. Volatility is a very good product, but not often updated especially with ...
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ctf kernel challenges does not work [closed]
I'm trying to learn and solve some 'kernel related' ctf challenges (reading writups to try to run same environment and achieve root using one of the kernel-pwn technique...).
I'm using Ubuntu 20 VM ...
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Can XIP (execute in place) be used for kernel protection?
Starting with kernel 5.13 RiscV will get XIP where parts of the kernel run from non volatile memory like flash. In theory you could make parts of the kernel really read only either from the hardware ...
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Vulnerability in which part of the Android architecture would allow an attacker to take control of the hardware [closed]
This question is intended for better understanding of security features of Android architecture.
In particular, I want to know what part of the architecture needs to be secure to prevent an attacker ...
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Security implications of automatic signing of kernel modules on Debian/Ubuntu (like VirtualBox does)
In the past, to install VirtualBox on Debian/Ubuntu you needed to sign some kernel modules, otherwise it would not work. The process involved creating a key pair, importing the public key as a MOK (...
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Does a (kernel) exploit always need to use system calls?
It was mentioned in this thread that kernel exploits usually use syscalls to trigger undesired behavior:
How can you detect kernel exploits?
Are there any ways or known examples which do not use ...
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Vulnerabilities for multiple kernel versions that are installed on a given server
As per Exclude or display vulnerabilities for non-running Linux kernels :
It is possible to have multiple kernels detected on a single Linux
host and Qualys will report all vulnerabilities found on ...
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Is it possible to determinate which functions a kernel module calls?
Trusting kernel drivers is bad. Is there something we can do to have at least an idea about what it does?
For example, let's suppose an armv8a linux kernel. I'd search for all the syscalls, which ...
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What are the dangers of a firmware malware in 2021 and is it possible?
I was reading a few articles online about how some firmware can be altered into malware and essentially infect a hardware equipment for its entire life time.
Like almost all SSDs in the industry ...
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Assigning memory address of shellcode to buffer (for buffer overflow input)
I am attempting to exploit HEVD kernel driver buffer overflow challenge:
https://github.com/hacksysteam/HackSysExtremeVulnerableDriver
However when running the below code my windows 7 machine doesn't ...
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How to get information about segments of physical memory not described in System.map on linux
When I do in linux root shell cat /boot/System.map-$(uname -r) it returns me segments of memory but there is a big gap around phys_startup_64:
00000000000228c0 D softnet_data
0000000000022a80 d ...
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Can a host OS be attacked through the network stack?
Forenote: I'm not familiar with how virtualisation works on a low-level (but I'd certainly like to learn) so this question could arise from ignorance.
Example Scenario: One virtualised router is ...
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Linux security modules (LSM) and reference monitor implementation
as far as my understanding goes, an OS needs to implement some sort of reference monitor, as the entity which grants or denies permissions as an access control decision.
Furthermore, I think the Linux ...
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How do you adjust offest and kernel stack size from an exploit?
Needless to I say I have no idea how to do this.
I'm performing a pentest and I found an exploit related the box : https://www.exploit-db.com/exploits/44298
In the exploit comments, the author said :
...
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Logging SSH commands on Linux - is custom kernel the only way?
I've done some research and it looks like that the way linux keeps history is less about security and audit and more about helping the user.
Even after making changes to instantly log the command and ...
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AES-256 ESSIV in dm-crypt
I am playing around with disk encryption. https://gitlab.com/cryptsetup/cryptsetup/-/wikis/DMCrypt#iv-generators says:
essiv: "encrypted sector|salt initial vector", the sector number is encrypted ...
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How to build Linux Volatility Profiles With the Compiled Kernel
I'm familiar with creating Linux memory profiles as stated here. However, this is assuming that I have access to the live system which often times is not the case.
I heard there is a way to build the ...
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Kernel ROP crashes running OS
I was experimenting to see if I can make an ROP chain within the kernel. In the kernel debugging mode, I can make the first jump to an arbitrary gadget address without any problem. But the problem ...
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What is the best way to restrict /proc fs from malicious users (linux)?
I am trying to make a restriction to procfs like only a certain groups of members can perform read and write actions.
kernel document says we can do that by setting hidepid and gid in /etc/fstab. It ...
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Vulnerable stored Linux kernel version
I am scanning Linux server which has two kernels versions stored, when I run following command I can see for example this version:
user@host [~]# rpm -q kernel
kernel-3.10.0-327.el7.x86_64
kernel-3....
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Kernel exploit fails after executing first command
While trying to solve old ctf task (https://blog.frizn.fr/plaidctf-2013/pwn-400-servr) I've encountered a situation which I don't understand.
TLTR
After escalating process privileges my exploit ...
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Is there a reasoning encrypting a GPL binary where I have to publish the sourcecode?
We're a company selling embedded devices. Our devices use u-boot & Linux, both being GPL and therefore we have to release the sourcecode as used to build our binary.
We're in the process of ...
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How to hide Kernel Symbols in Linux Kernel Image? Recompliation?
Why hide kernel symbols?
Quote
Anyone with basic knowledge of kernel exploitation knows how important information gathering is to reliable exploitation. This protection hides the kernel symbols ...
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Can a non-privileged user modify the file descriptor table of an elevated process?
In Linux, every process holds its own file descriptor table, which keeps references to all opened files and file-like devices. This table is managed by the kernel.
Is it possible that a non-...
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Is it necessary to understand Linux kernel internals to do binary exploitation? [closed]
I am second-year CS student, I know C, OOP concepts, x86 architecture, reverse engineering basics, TCP/IP stack and OS concepts, also I love Linux OS.
I have just one question:
Is it a mandatory to ...
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Is exploit different from the kernel level or root?
I'm learning about privilege escalation.
I'm trying exploits in my lab machine like vulnhub.
In my opinion, if I successfully run the exploit linux/local/udev/net_link, I can read etc/shadow and etc/...
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Securing IPC between kernel and user-mode application
We are currently developing a security software for Windows. This application consists of a service running in user mode and a driver in kernel mode. These two need to communicate, so that the service ...
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