CVE-2017-1000253 PoC — Linux kernel 缓冲区错误漏洞

Source

https://github.com/RicterZ/PIE-Stack-Clash-CVE-2017-1000253

Associated Vulnerability

Title: Linux kernel 缓冲区错误漏洞 (CVE-2017-1000253)
Description:Linux distributions that have not patched their long-term kernels with https://git.kernel.org/linus/a87938b2e246b81b4fb713edb371a9fa3c5c3c86 (committed on April 14, 2015). This kernel vulnerability was fixed in April 2015 by commit a87938b2e246b81b4fb713edb371a9fa3c5c3c86 (backported to Linux 3.10.77 in May 2015), but it was not recognized as a security threat. With CONFIG_ARCH_BINFMT_ELF_RANDOMIZE_PIE enabled, and a normal top-down address allocation strategy, load_elf_binary() will attempt to map a PIE binary into an address range immediately below mm->mmap_base. Unfortunately, load_elf_ binary() does not take account of the need to allocate sufficient space for the entire binary which means that, while the first PT_LOAD segment is mapped below mm->mmap_base, the subsequent PT_LOAD segment(s) end up being mapped above mm->mmap_base into the are that is supposed to be the "gap" between the stack and the binary.

Description

Demo-ing CVE-2017-1000253 in a container

Readme

# PIE-Stack-Clash-CVE-2017-1000253
Demo-ing CVE-2017-1000253 in a container.
This demo relies on [Qualys POC code](https://www.qualys.com/research/security-advisories/?_ga=2.83676118.1784152149.1507102441-274088665.1506491591) that performs the exploit over CentOS.
## Install a vulnerable kernel

    1.Install CentOS 7
    2.Install Docker
    3.Edit the /etc/yum.repos.d/CentOS-Vault.repo file:
         1.Change each entry to path to include 7.3.1611:
                  baseurl=http://vault.centos.org/7.3.1611/os/$basearch/
                  baseurl=http://vault.centos.org/7.3.1611/updates/$basearch/
                  ...
         2.Enable all the entries:
                  enabled=1
     4.Update the repo list
         yum repolist
     5.Install a vulnerable kernel 
         yum install kernel-3.10.0-514.26.1.el7.x86_64
     6.Check the kernel ID (in the following example, it is 0):
        # awk -F\' '$1=="menuentry " {print i++ " : " $2}' /etc/grub2.cfg0 
           0 : CentOS Linux (3.10.0-514.26.1.el7.x86_64) 7 (Core)
           1 : CentOS Linux (3.10.0-514.26.1.el7.x86_64) 7 (Core) with debugging
           2 : CentOS Linux 7 (Core), with Linux 3.10.0-229.20.1.el7.x86_64
     7.Set the default entry for grub:
         grub2-set-default 0
     8.Make sure it had changed:
       # grub2-editenv list
         saved_entry=0
     9.Reboot
       shutdown -r now
    10.Make sure the vulnerable kernel was loaded
       # uname -a
         Linux devSDces71b305-vm0 3.10.0-514.26.1.el7.x86_64 #1 SMP Thu Jun 29 16:05:25 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
## Build the container
``` sh
docker build -t pie-cve .
```
## Run the container an a non-root user
``` sh
docker run -it -u 4444 pie-cve
```
Normally, after a few hours the exploit will be done. The "hacker.txt" file will be written the /root directory inside the container.

File Snapshot

Remarks

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