Obfuscated Files or Information
Adversaries may attempt to make an executable or file difficult to discover or analyze by encrypting, encoding, or otherwise obfuscating its contents on the system or in transit. This is common behavior that can be used across different platforms and the network to evade defenses. Payloads may be compressed, archived, or encrypted in order to avoid detection. These payloads may be used during Initial Access or later to mitigate detection. Sometimes a user's action may be required to open and Deobfuscate/Decode Files or Information for User Execution. The user may also be required to input a password to open a password protected compressed/encrypted file that was provided by the adversary. Adversaries may also use compressed or archived scripts, such as JavaScript. Portions of files can also be encoded to hide the plain-text strings that would otherwise help defenders with discovery. Payloads may also be split into separate, seemingly benign files that only reveal malicious functionality when reassembled. Adversaries may also abuse Command Obfuscation to obscure commands executed from payloads or directly via Command and Scripting Interpreter. Environment variables, aliases, characters, and other platform/language specific semantics can be used to evade signature based detections and application control mechanisms.
Open detection, hunting, mitigation, and evidence workspace
Detection logic
Detection of file obfuscation is difficult unless artifacts are left behind by the obfuscation process that are uniquely detectable with a signature. If detection of the obfuscation itself is not possible, it may be possible to detect the malicious activity that caused the obfuscated file (for example, the method that was used to write, read, or modify the file on the file system). Flag and analyze commands containing indicators of obfuscation and known suspicious syntax such as uninterpreted escape characters like '''^''' and '''"'''. Windows' Sysmon and Event ID 4688 displays command-line arguments for processes. Deobfuscation tools can be used to detect these indicators in files/payloads. Obfuscation used in payloads for Initial Access can be detected at the network. Use network intrusion detection systems and email gateway filtering to identify compressed and encrypted attachments and scripts. Some email attachment detonation systems can open compressed and encrypted attachments. Payloads delivered over an encrypted connection from a website require encrypted network traffic inspection. The first detection of a malicious tool may trigger an anti-virus or other security tool alert. Similar events may also occur at the boundary through network IDS, email scanning appliance, etc. The initial detection should be treated as an indication of a potentially more invasive intrusion. The alerting system should be thoroughly investigated beyond that initial alert for activity that was not detected. Adversaries may continue with an operation, assuming that individual events like an anti-virus detect will not be investigated or that an analyst will not be able to conclusively link that event to other activity occurring on the network.
Observed actors
Correlated CTI and IR reports
1200km CTI repository · explicit report mentionATT&CK as a Working Tool: Theory and Hands-On Practical Usage
1200km CTI repository · explicit report mentionCTI Research: Kubernetes & Cloud-Native Threat Landscape
1200km CTI repository · explicit report mentionCTI Research: MuddyWater / Seedworm (Mango Sandstorm)
1200km CTI repository · explicit report mentionCTI Research: MuddyWater / Seedworm (Mango Sandstorm)
1200km CTI repository · explicit report mentionExecutive Summary
Israel Threat Actors CTI · explicit report mentionFrom Threat Intelligence to Detection: A Practitioner's Guide
1200km CTI repository · explicit report mentionOperation DragonRx — APT41 Full Attack Simulation
1200km CTI repository · explicit report mentionOperation DragonRx: Simulating an APT41 Attack End-to-End — From Log4Shell to DFIR and Malware Analysis
1200km CTI repository · explicit report mentionATT CK as a Working Tool Theory and Hands On Practical Usage
1200km Medium · authored report mentionCTI Research Kubernetes Cloud Native Threat Landscape
1200km Medium · authored report mentionCTI Research MuddyWater Seedworm Mango Sandstorm
1200km Medium · authored report mentionFrom Threat Intelligence to Detection A Practitioner s Guide
1200km Medium · authored report mention