Update v8.18.12

Command Line Obfuscation via Whitespace Padding

Identifies process execution events where the command line value contains a long sequence of whitespace characters or multiple occurrences of contiguous whitespace. Attackers may attempt to evade signature-based detections by padding their malicious command with unnecessary whitespace characters. These observations should be investigated for malicious behavior.

new

1

Potential Web Shell ASPX File Creation

Identifies the creation of ASPX files in specific directories that are commonly targeted by attackers to deploy web shells.

new

1

Microsoft Entra ID Suspicious Session Reuse to Graph Access

Identifies potential session hijacking or token replay in Microsoft Entra ID. This rule detects cases where a user signs in and subsequently accesses Microsoft Graph from a different IP address using the same session ID. This may indicate a successful OAuth phishing attack, session hijacking, or token replay attack, where an adversary has stolen a session cookie or refresh/access token and is impersonating the user from an alternate host or location.

update

4

MFA Deactivation with no Re-Activation for Okta User Account

Detects multi-factor authentication (MFA) deactivation with no subsequent re-activation for an Okta user account. An adversary may deactivate MFA for an Okta user account in order to weaken the authentication requirements for the account.

update

416

Connection to Commonly Abused Web Services

Adversaries may implement command and control (C2) communications that use common web services to hide their activity. This attack technique is typically targeted at an organization and uses web services common to the victim network, which allows the adversary to blend into legitimate traffic activity. These popular services are typically targeted since they have most likely been used before compromise, which helps malicious traffic blend in.

update

121

Creation or Modification of Root Certificate

Identifies the creation or modification of a local trusted root certificate in Windows. The install of a malicious root certificate would allow an attacker the ability to masquerade malicious files as valid signed components from any entity (for example, Microsoft). It could also allow an attacker to decrypt SSL traffic.

update

314

PowerShell Script Block Logging Disabled

Identifies attempts to disable PowerShell Script Block Logging via registry modification. Attackers may disable this logging to conceal their activities in the host and evade detection.

update

313

Potential Windows Error Manager Masquerading

Identifies suspicious instances of the Windows Error Reporting process (WerFault.exe or Wermgr.exe) with matching command-line and process executable values performing outgoing network connections. This may be indicative of a masquerading attempt to evade suspicious child process behavior detections.

update

214

Potential PowerShell Obfuscation via Invalid Escape Sequences

Identifies PowerShell scripts that use invalid escape sequences as a form of obfuscation. This technique introduces backticks (`) between characters in a way that does not correspond to valid PowerShell escape sequences, breaking up strings and bypassing pattern-based detections while preserving execution logic. This is designed to evade static analysis and bypass security protections such as the Antimalware Scan Interface (AMSI).

update

5

Potential PowerShell Obfuscation via High Numeric Character Proportion

Identifies PowerShell scripts with a disproportionately high number of numeric characters, often indicating the presence of obfuscated or encoded payloads. This behavior is typical of obfuscation methods involving byte arrays, character code manipulation, or embedded encoded strings used to deliver and execute malicious content.

update

5

Potential Dynamic IEX Reconstruction via Environment Variables

Identifies PowerShell scripts that reconstruct the IEX (Invoke-Expression) command at runtime using indexed slices of environment variables. This technique leverages character access and join operations to build execution logic dynamically, bypassing static keyword detection and evading defenses such as AMSI.

update

4

Dynamic IEX Reconstruction via Method String Access

Identifies PowerShell scripts that reconstruct the IEX (Invoke-Expression) command by accessing and indexing the string representation of method references. This obfuscation technique uses constructs like ''.IndexOf.ToString() to expose method metadata as a string, then extracts specific characters through indexed access and joins them to form IEX, bypassing static keyword detection and evading defenses such as AMSI.

update

5

Potential PowerShell Obfuscation via Reverse Keywords

Identifies PowerShell scripts that use reversed strings as a form of obfuscation. These methods are designed to evade static analysis and bypass security protections such as the Antimalware Scan Interface (AMSI).

update

4

Potential PowerShell Obfuscation via String Reordering

Identifies PowerShell scripts that use string reordering and runtime reconstruction techniques as a form of obfuscation. These methods are designed to evade static analysis and bypass security protections such as the Antimalware Scan Interface (AMSI).

update

6

Potential RemoteMonologue Attack

Identifies attempt to perform session hijack via COM object registry modification by setting the RunAs value to Interactive User.

update

3

Unusual Child Processes of RunDLL32

Identifies child processes of unusual instances of RunDLL32 where the command line parameters were suspicious. Misuse of RunDLL32 could indicate malicious activity.

update

212

Unusual Process Execution Path - Alternate Data Stream

Identifies processes running from an Alternate Data Stream. This is uncommon for legitimate processes and sometimes done by adversaries to hide malware.

update

314

Unusual Network Connection via RunDLL32

Identifies unusual instances of rundll32.exe making outbound network connections. This may indicate adversarial Command and Control activity.

update

212

Suspicious Windows Powershell Arguments

Identifies the execution of PowerShell with suspicious argument values. This behavior is often observed during malware installation leveraging PowerShell.

update

207

Unusual Persistence via Services Registry

Identifies processes modifying the services registry key directly, instead of through the expected Windows APIs. This could be an indication of an adversary attempting to stealthily persist through abnormal service creation or modification of an existing service.

update

314

Suspicious PrintSpooler Service Executable File Creation

Detects attempts to exploit privilege escalation vulnerabilities related to the Print Spooler service. For more information refer to the following CVE’s - CVE-2020-1048, CVE-2020-1337 and CVE-2020-1300 and verify that the impacted system is patched.

update

318