Trojan.Win32.Yakes.abnjv

Adversaries may exploit software vulnerabilities in client applications to execute code. Vulnerabilities can exist in software due to unsecure coding practices that can lead to unanticipated behavior. Adversaries can take advantage of certain vulnerabilities through targeted exploitation for the purpose of arbitrary code execution. Oftentimes the most valuable exploits to an offensive toolkit are those that can be used to obtain code execution on a remote system because they can be used to gain access to that system. Users will expect to see files related to the applications they commonly used to do work, so they are a useful target for exploit research and development because of their high utility.

Several types exist:

### Browser-based Exploitation

Web browsers are a common target through Drive-by Compromise and Spearphishing Link. Endpoint systems may be compromised through normal web browsing or from certain users being targeted by links in spearphishing emails to adversary controlled sites used to exploit the web browser. These often do not require an action by the user for the exploit to be executed.

### Office Applications

Common office and productivity applications such as Microsoft Office are also targeted through Phishing. Malicious files will be transmitted directly as attachments or through links to download them. These require the user to open the document or file for the exploit to run.

### Common Third-party Applications

Other applications that are commonly seen or are part of the software deployed in a target network may also be used for exploitation. Applications such as Adobe Reader and Flash, which are common in enterprise environments, have been routinely targeted by adversaries attempting to gain access to systems. Depending on the software and nature of the vulnerability, some may be exploited in the browser or require the user to open a file. For instance, some Flash exploits have been delivered as objects within Microsoft Office documents.

An adversary may attempt to block indicators or events typically captured by sensors from being gathered and analyzed. This could include maliciously redirecting(Citation: Microsoft Lamin Sept 2017) or even disabling host-based sensors, such as Event Tracing for Windows (ETW)(Citation: Microsoft About Event Tracing 2018), by tampering settings that control the collection and flow of event telemetry.(Citation: Medium Event Tracing Tampering 2018) These settings may be stored on the system in configuration files and/or in the Registry as well as being accessible via administrative utilities such as PowerShell or Windows Management Instrumentation.

For example, adversaries may modify the `File` value in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\EventLog\Security to hide their malicious actions in a new or different .evtx log file. This action does not require a system reboot and takes effect immediately.(Citation: disable_win_evt_logging)

ETW interruption can be achieved multiple ways, however most directly by defining conditions using the PowerShell Set-EtwTraceProvider cmdlet or by interfacing directly with the Registry to make alterations.

In the case of network-based reporting of indicators, an adversary may block traffic associated with reporting to prevent central analysis. This may be accomplished by many means, such as stopping a local process responsible for forwarding telemetry and/or creating a host-based firewall rule to block traffic to specific hosts responsible for aggregating events, such as security information and event management (SIEM) products.

In Linux environments, adversaries may disable or reconfigure log processing tools such as syslog or nxlog to inhibit detection and monitoring capabilities to facilitate follow on behaviors (Citation: LemonDuck).