Questions tagged [kernel]

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Tips for auditing/finding a better/trusted source for an anonymous but open source network device linux driver from some random github repo

Maybe because I am a cheap bastard or just because I saw no better alternative in the market in terms of reported performance and functionality vs. size, I bought this USB bluetooth/WiFi5 dongle: ...
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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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Is W^X enforced against UEFI DXE drivers (firmware)? Could it be if we tried?

W^X is a critical security feature, allowing us a chance to perform security analysis on data that some entity on a computer wants to execute. Windows implements this by requiring a process to call ...
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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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Should Parrot Sec Contain 3 sys_call_table?

I noticed that if I grep the system.map in Parrot Sec 4.10 for sys_call_table it returns three results. I have reason to believe the workstation I first did this on was compromised, so I installed a ...
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1answer
166 views

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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bluetooth link encrytion under bluetooth 4 .2 and 5.x

This is a follow up question regarding this answer In Linux does the encryption of the bluetooth link using bluetooth 4.2 or 5.x depend on the version of the kernel - and whether or not the kernel ...
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399 views

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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1answer
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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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1answer
203 views

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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1answer
447 views

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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1answer
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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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1answer
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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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1answer
96 views

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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1answer
211 views

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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308 views

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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1answer
239 views

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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314 views

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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1answer
263 views

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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1answer
188 views

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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119 views

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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1answer
781 views

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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1answer
227 views

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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1answer
378 views

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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1answer
98 views

Is exploit different from the kernel level or root?

i'm searching privilage escalation. there is some way if you looking at. i trying exploit in my lab machine like vulnhub. there is a diagram for understanding differents. anyway I told you a little. ...
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1answer
256 views

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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447 views

VDSL modem getting probed?

My ZyXEL VMG8924-B30A VDSL modem recently had these alerts in its log. The WAN IP address of the modem is 10.225.205.128. There was nothing like this before 1 May. What is this? 2019 -05 -01 T16:05:...
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188 views

Why it is difficult to write an application to protect 100% against keyloggers?

When you press keystrokes, I suppose you can intercept in low level code all applications that listen and record. Why it cannot be designed a software that protects 100% against keyloggers, simply ...
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808 views

linux kernel exploit shellcode causes segfault

I'm learning how to write kernel exploits and my shellcode keeps seg faulting. I'm getting the memory address for commit_creds(prepare_kernel_cred(0)); #grep commit_creds /proc/kallsyms c907eea0 T ...
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172 views

Secure way to sign virtualbox module for secure boot

I'm not sure if the Virtualbox version from the repository of my Linux distribution is already signed and works right away, but since it's not up-to-date I'm installing Virtualbox from the official ...
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How is CVE-2016-6787 a UAF bug in Linux kernel?

From the explanation video of the Linux kernel vulnerability CVE-2016-6787, I don't understand is though put_ctx isn't inside a mutex, there's an atomic_dec_and_test inside put_ctx at the very ...
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1answer
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Is Meltdown/Spectre mitigation necessary in virtual machine as well as in hypervisor? [duplicate]

I am running virtual machines in kvm/qemu hypervisor. The hypervisor has Meltdown/Spectre mitigation enabled in kernel. Is it necessary that virtual machines have the Meltdown/Spectre mitigation ...
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Identifying kernel pointer infoleaks via static analysis

Leaking pointers from the kernel can be useful to an attacker. Normally, pointers are printed using a special identifier, %pK, which will sanitize them. However, there are times when a kernel pointer ...
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1answer
351 views

Does printk() cause any security issues?

I'm asking myself if the function printk() causes security issues on Linux. When an attacker has user level access to the system, does it make his life easier if he has access to kernel pointers? Does ...
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1answer
628 views

Is Debian 9.5 stretch vulnerable to CVE-2018-17182?

I have a Debian system running the following kernel version: Linux REDACTED 4.9.0-7-amd64 #1 SMP Debian 4.9.110-3+deb9u2 (2018-08-13) x86_64 GNU/Linux Linux REDACTED 4.9.0-7-amd64 #1 SMP Debian 4.9....
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2answers
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How protected mode in CPU is really implemented?

I know what is real and protected mode of cpu execution. But how CPU implements protected mode ? AFAIK cpu does everything what the program says it to do. Where is the protected mode behaviour ...
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1answer
907 views

The older the Linux kernel is, the more secure?

Are there security benefits running Linux Distro base on an older version of Linux kernel? Security benefits = fewer vulnerabilities that can be exploited by hackers. Linux Distro base on older ...
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1answer
330 views

How to fix Spectre variant 3a and variant 4?e

How I can fix CVE-2018-3640 [rogue system register read] aka 'Variant 3a' and CVE-2018-3639 [speculative store bypass] aka 'Variant 4'? My status for them is VULNERABLE. I have Intel CPU and using ...
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Is there any modern scalable way to do system call monitoring?

I wrote a kernel module to replace the Linux kernel service routines (e.g. system calls) with security-enforcing code, similar to SELinux or AppArmor, with the main exceptions of ruleset control on-...