Linux Heap TCache Free Chunk Information Disclosure


In this paper, I introduce the reader what is in a free tcache chunk. There are two pointers maintained in these free chunks that leak information about the address layout and internal allocator structures. This paper will discuss those leaks.

Linux Heap TCache Free Chunk Information Disclosure.PDF 

Comments

Post a Comment

Popular posts from this blog

Linux Kernel Stack Smashing

Dr Silvio Cesare @silviocesare   Summary In this blog post I’ll discuss how to exploit the Linux kernel via a stack smashing attack. I’ll be attacking the latest kernel version. I’ll also introduce a vulnerable device driver that I wrote so that I can focus on the exploitation development and not the vulnerability research.  A number of mitigations were introduced in recent years, such as Kernel Page Table Isolation and control register pinning, which makes some previous techniques obsolete. Techniques like ret2usr no longer work. But regardless, I am able to privesc and gain a rootshell. An overview of the attack The attack can be split up into a number of stages: ·         Defeat KASLR ·         Leak the stack canary ·         Stack smash and overwrite the canary and return address to trigger a ROP chain ·         ROP to change the current creds to UID 0 ·         ROP into the code that returns from a system call and continues execution i
Read more

Sudoedit heap overflow

Jayden Rivers @Awarau1 Introduction On January 27th 2021 Qualys released a report on a bug they had found in the commonly used Unix utility: sudo . The bug had been present in sudo for nearly 10 years. Their report, which can be found here CVE-2021-3156: Heap-Based Buffer Overflow in Sudo (Baron Samedit) | Qualys Security Blog , outlines the root cause and three possible methods of exploitation. Here, we give a brief overview of the relevant workings of sudo. Then we discuss the vulnerability as well as one possible exploitation method in depth. The details of exploitation will focus on our application of the technique known as “heap grooming” or “heap feng shui”. Lastly, we outline the fix.    Sudo (utility) Sudo, or “superuser do”, is a widely used utility which assists people in administrating their Unix systems. Many Unix derived operating systems have sudo packaged by default.  According to the sudo manual , “sudo allows a permitted user to execute a command as the superuser or a
Read more

Pointer Compression in V8

Image
Syed Faraz Abrar @farazsth98   Summary In this blog post, I will provide some details on how the Chromium developers implemented pointer compression in V8. I will also talk about what this means from an exploit development perspective. Introduction I’ve been an intern at InfoSect for the past couple of weeks now, and in this time, I’ve had to do a bunch of security related research into both V8 and Spidermonkey. One of the things that I spent a short amount of my time on was pointer compression in V8. I hadn’t heard of the term at all until Bruno Keith ( @bkth_ ) mentioned it on twitter some time in December last year. The V8 developers also made a blog post to celebrate V8 v8.0 where they mentioned that implementing pointer compression had allowed them to save up to 40% in usage of heap memory! That’s a big improvement, so let’s take a look at what pointer compression is and what it means from an exploit developer’s perspective. Disclaimer This is not intended to
Read more