T1027 Obfuscated Files or Information

This diagnostic statement provides for implementation of methods to block similar future attacks via security tools such as antivirus and IDS/IPS to provide protection against threats and exploitation attempts.

This diagnostic statement implements technical controls (e.g., VPN, antivirus software) to address the risks of end-user personal computing devices accessing the organization’s network and resources.

Antivirus/Antimalware software can be utilized to detect and quarantine suspicious files that adversaries have made difficult to discover by encrypting, encoding, or obfuscating.

This diagnostic statement provides for securely configuring production systems. This includes hardening default configurations and making security-focused setting adjustments to reduce the attack surface, enforce best practices, and protect sensitive data thereby mitigating adversary exploitation.

This diagnostic statement protects against Obfuscated Files or Information through the use of limiting access to resources to only authorized devices, management of personal computing devices, network intrusion prevention, and the use of antimalware.

This vulnerability is exploited by an attacker who has obtained administrative console access on the target system. The vulnerability lies in the Win32k driver, specifically in the NtGdiResetDC function, due to improper handling of user-mode callbacks. This vulnerability has been exploited by threat actors to gain elevated privileges on Windows servers. Attackers leveraged this flaw to execute arbitrary kernel commands, allowing them to manipulate system processes and deploy additional malware to perform further malicious activities. The exploit in question is actively being used in the wild, primarily in espionage campaigns. It involves triggering a use-after-free condition by executing the ResetDC function a second time for the same handle during a callback. Once the vulnerability is exploited, attackers can manipulate memory to perform arbitrary kernel function calls with controlled parameters. This allows them to achieve their objectives, such as reading and writing kernel memory, with the same permissions as the compromised system's user.

This vulnerability is exploited by the user opening a malicious pdf file to achieve arbitrary code execution.

CVE-2021-44077 is an unauthenticated remote code execution vulnerability. The following post-exploitation activity has been observed by adversaries: writing webshells to disk for persistence, obfuscating and deobfuscating/decoding files or information, dumping user credentials, only using signed windows binaries for follow-on actions, adding/deleting user accounts as needed, exfiltrating the active directory database, using windows management instrumentation for remote execution, deleting files to remove indicators from the host, discovering domain accounts, collecting and archiving files for exfiltration, and using symmetric encryption for command and control.

This vulnerability can be exploited via a public-facing e-commerce application in order to achieve remote code execution. To evade detection, the exploit segment responsible for downloading and executing the remote malicious PHP code is obfuscated.

This is an authentication bypass vulnerability that can enable remote code execution. Numerous post-exploitation impacts by threat actors are detailed in the referenced CISA report.

The Microsoft Sentinel Analytics "Powershell Empire cmdlets seen in command line" query can detect the use of Empire, which can obfuscate commands using Invoke-Obfuscation, but does not address other procedures.

This control only provides detection coverage for the Compile After Delivery sub-technique while not providing detection for all other sub-techniques relevant to the Linux platform or most of its procedure examples. As a result of this minimal coverage, the overall score is assessed as Minimal.

This control may detect usage of VBScript.Encode and base-64 encoding to obfuscate malicious commands and scripts. The following alerts may be generated: "Detected suspicious execution of VBScript.Encode command", "Detected encoded executable in command line data".

This control only covers one platform and procedure for one of this technique's sub-techniques, resulting in a Minimal score.

This control can detect file obfuscation.

This control can prevent file obfuscation.

Google Security Ops is able to trigger an alert based off suspicious command line arguments or processes that indicate obfuscation techniques to evade cyber defenses. For example, when cmd.exe has been obfuscated. This mapping was scored as minimal based on low or uncertain detection coverage factor of the technique. https://github.com/chronicle/detection-rules/blob/783e0e5947774785db1c55041b70176deeca6f46/soc_prime_rules/threat_hunting/windows/detect_cmd_exe_obfuscation.yaral https://github.com/chronicle/detection-rules/blob/783e0e5947774785db1c55041b70176deeca6f46/soc_prime_rules/threat_hunting/windows/ursnif_trojan_detection__cmd_obfuscation.yaral

In Microsoft 365 organizations with mailboxes in Exchange Online or standalone Exchange Online Protection (EOP) organizations without Exchange Online mailboxes, email messages are automatically protected against malware by EOP. Some of the major categories of malware are: Viruses that infect other programs and data, and spread through your computer or network looking for programs to infect. Spyware that gathers your personal information, such as sign-in information and personal data, and sends it back to its author. Ransomware that encrypts your data and demands payment to decrypt it. Anti-malware software doesn't help you decrypt encrypted files, but it can detect the malware payload that's associated with the ransomware. EOP offers multi-layered malware protection that's designed to catch all known malware in Windows, Linux, and Mac that travels into or out of your organization. The following options help provide anti-malware protection: Layered defenses against malware: Multiple anti-malware scan engines help protect against both known and unknown threats. These engines include powerful heuristic detection to provide protection even during the early stages of a malware outbreak. This multi-engine approach has been shown to provide significantly more protection than using just one anti-malware engine. Real-time threat response: During some outbreaks, the anti-malware team might have enough information about a virus or other form of malware to write sophisticated policy rules that detect the threat, even before a definition is available from any of the scan engines used by the service. These rules are published to the global network every 2 hours to provide your organization with an extra layer of protection against attacks. Fast anti-malware definition deployment: The anti-malware team maintains close relationships with partners who develop anti-malware engines. As a result, the service can receive and integrate malware definitions and patches before they're publicly released. Our connection with these partners often allows us to develop our own remedies as well. The service checks for updated definitions for all anti-malware engines every hour. License Requirements: M365 E3 or Microsoft Defender for Office plan 1.

In Exchange Online Protection (EOP) and Microsoft Defender for Office 365, quarantine policies allow admins to define the user experience for quarantined messages. Traditionally, users have been allowed or denied levels of interactivity with quarantine messages based on why the message was quarantined. For example, users can view and release messages that were quarantined as spam or bulk, but they can't view or release messages that were quarantined as high confidence phishing or malware. The following M365 features are supported by quarantine policies, “Response” to Anti-malware and Anti-Phishing tagged items. Files that are quarantined as malware by Safe Attachments for SharePoint, OneDrive, and Microsoft Teams. License requirements: M365 E3 (or Defender for Office plan 1)

Zero-hour auto purge (ZAP) is a protection feature in Exchange Online Protection (EOP) that retroactively detects and neutralizes malicious phishing, spam, or malware messages that have already been delivered to Exchange Online mailboxes. With the E5 licensing or Office Plan 2, ZAP is also able to retroactively detect existing malicious chat messages in Microsoft Teams that are identified as malware or high confidence phishing. License Requirements: ZAP for Defender O365 is included with M365's E3 and requires E5 when leveraging ZAP for Teams security.