W3WP Spawning Shell: endpointEndpointrisk_score:562024-09-30version:4
The following analytic identifies instances where a shell (PowerShell.exe or Cmd.exe) is spawned from W3WP.exe, the IIS worker process. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process creation events where the parent process is W3WP.exe. This activity is significant as it may indicate webshell activity, often associated with exploitation attempts like those by the HAFNIUM Group on Exchange servers. If confirmed malicious, this behavior could allow attackers to execute arbitrary commands, potentially leading to system compromise, data exfiltration, or further lateral movement within the network.
Detect Webshell Exploit Behavior: endpointEndpointrisk_score:802024-11-28version:5
The following analytic identifies the execution of suspicious processes typically associated with webshell activity on web servers. It detects when processes like `cmd.exe`, `powershell.exe`, or `bash.exe` are spawned by web server processes such as `w3wp.exe` or `nginx.exe`. This behavior is significant as it may indicate an adversary exploiting a web application vulnerability to install a webshell, providing persistent access and command execution capabilities. If confirmed malicious, this activity could allow attackers to maintain control over the compromised server, execute arbitrary commands, and potentially escalate privileges or exfiltrate sensitive data.
Exchange PowerShell Abuse via SSRF: endpointEndpointrisk_score:802024-10-17version:4
The following analytic detects suspicious behavior indicative of ProxyShell exploitation against on-premise Microsoft Exchange servers. It identifies HTTP POST requests to `autodiscover.json` containing `PowerShell` in the URI, leveraging server-side request forgery (SSRF) to access backend PowerShell. This detection uses Exchange server logs ingested into Splunk. Monitoring this activity is crucial as it may indicate an attacker attempting to execute commands or scripts on the Exchange server. If confirmed malicious, this could lead to unauthorized access, privilege escalation, or persistent control over the Exchange environment.
Exchange PowerShell Module Usage: endpointEndpointrisk_score:322024-09-30version:7
The following analytic detects the usage of specific Exchange PowerShell modules, such as New-MailboxExportRequest, New-ManagementRoleAssignment, New-MailboxSearch, and Get-Recipient. It leverages PowerShell Script Block Logging (EventCode 4104) to identify these commands. This activity is significant because these modules can be exploited by adversaries who have gained access via ProxyShell or ProxyNotShell vulnerabilities. If confirmed malicious, attackers could export mailbox contents, assign management roles, conduct mailbox searches, or view recipient objects, potentially leading to data exfiltration, privilege escalation, or unauthorized access to sensitive information.
Windows MSExchange Management Mailbox Cmdlet Usage: endpointEndpointrisk_score:322024-09-30version:3
The following analytic identifies suspicious Cmdlet usage in Exchange Management logs, focusing on commands like New-MailboxExportRequest and New-ManagementRoleAssignment. It leverages EventCode 1 and specific Message patterns to detect potential ProxyShell and ProxyNotShell abuse. This activity is significant as it may indicate unauthorized access or manipulation of mailboxes and roles, which are critical for maintaining email security. If confirmed malicious, attackers could export mailbox data, assign new roles, or search mailboxes, leading to data breaches and privilege escalation.
CertUtil Download With URLCache and Split Arguments: endpointEndpointrisk_score:902024-12-07version:8
The following analytic detects the use of certutil.exe to download files using the `-urlcache` and `-f` arguments. It leverages Endpoint Detection and Response (EDR) data, focusing on command-line executions that include these specific arguments. This activity is significant because certutil.exe is typically used for certificate services, and its use to download files from remote locations is uncommon and potentially malicious. If confirmed, this behavior could indicate an attempt to download and execute malicious payloads, leading to potential system compromise and unauthorized data access.
CMD Carry Out String Command Parameter: endpointEndpointrisk_score:302024-10-17version:6
The following analytic detects the use of `cmd.exe /c` to execute commands, a technique often employed by adversaries and malware to run batch commands or invoke other shells like PowerShell. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions and process metadata. Monitoring this activity is crucial as it can indicate script-based attacks or unauthorized command execution. If confirmed malicious, this behavior could lead to unauthorized code execution, privilege escalation, or persistence within the environment.
Detect Exchange Web Shell: endpointEndpointrisk_score:812024-12-12version:9
The following analytic identifies the creation of suspicious .aspx files in known drop locations for Exchange exploitation, specifically targeting paths associated with HAFNIUM group and vulnerabilities like ProxyShell and ProxyNotShell. It leverages data from the Endpoint datamodel, focusing on process and filesystem events. This activity is significant as it may indicate a web shell deployment, a common method for persistent access and remote code execution. If confirmed malicious, attackers could gain unauthorized access, execute arbitrary commands, and potentially escalate privileges within the Exchange environment.
ProxyShell ProxyNotShell Behavior Detected: networkWeb Serverrisk_score:812024-09-30version:3
The following analytic identifies potential exploitation of Windows Exchange servers via ProxyShell or ProxyNotShell vulnerabilities, followed by post-exploitation activities such as running nltest, Cobalt Strike, Mimikatz, and adding new users. It leverages data from multiple analytic stories, requiring at least five distinct sources to trigger, thus reducing noise. This activity is significant as it indicates a high likelihood of an active compromise, potentially leading to unauthorized access, privilege escalation, and persistent threats within the environment. If confirmed malicious, attackers could gain control over the Exchange server, exfiltrate data, and maintain long-term access.
Windows Exchange Autodiscover SSRF Abuse: networkWeb Serverrisk_score:722024-09-30version:3
The following analytic detects potential abuse of the ProxyShell or ProxyNotShell vulnerabilities in Microsoft Exchange via Server Side Request Forgery (SSRF). It leverages the Web datamodel to identify suspicious POST requests with specific URI paths and queries related to autodiscover, powershell, and mapi. This activity is significant as it may indicate an attempt to exploit Exchange server vulnerabilities to access internal services or sensitive data. If confirmed malicious, this could lead to unauthorized access, data exfiltration, or further compromise of the network.
