""ET WEB_SERVER LEMURLOOT WebShell Interaction Header - X-siLock-Step1 -1 Data Exfil Response - Observed in MOVEit File Transfer - OUTBOUND (Active Compromise)""

SID: 2046050

Revision: 1

Class Type: successful-admin

Metadata: attack_target Web_Server, created_at 2023_06_02, deployment Perimeter, deployment SSLDecrypt, malware_family LEMURLOOT, performance_impact Low, confidence High, signature_severity Critical, tag WebShell, updated_at 2023_06_02

Reference:

Protocol: tcp

Source Network: [$HOME_NET,$HTTP_SERVERS]

Source Port: any

Destination Network: $EXTERNAL_NET

Destination Port: any

Flow: established,to_client

Contents:

  • Value: "X-siLock-Comment|3a 20|"

  • Value: "AzureBlobStorageAccount|3a 20|"

  • Value: "AzureBlobKey|3a 20|"

  • Value: "AzureBlobContainer|3a 20|"

Within:

PCRE:

Special Options:

  • http_header

  • http_header

  • http_header

  • http_header

source