System Language Discovery
Where this stands
One published detection covers this technique. Every one is unverified — no rule on Siemphony has been executed against real telemetry.
What the technique is
Adversaries may attempt to gather information about the system language of a victim in order to infer the geographical location of that host. This information may be used to shape follow-on behaviors, including whether the adversary infects the target and/or attempts specific actions. This decision may be employed by malware developers and operators to reduce their risk of attracting the attention of specific law enforcement agencies or prosecution/scrutiny from other entities. There are various sources of data an adversary could use to infer system language, such as system defaults and keyboard layouts. Specific checks will vary based on the target and/or adversary, but may involve behaviors such as Query Registry and calls to Native API functions. For example, on a Windows system adversaries may attempt to infer the language of a system by querying the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\Language or parsing the outputs of Windows API functions GetUserDefaultUILanguage, GetSystemDefaultUILanguage, GetKeyboardLayoutList and GetUserDefaultLangID. On a macOS or Linux system, adversaries may query locale to retrieve the value of the $LANG environment variable.
Read it on attack.mitre.orgWhat MITRE says you would watch
- AN1561
Registry access to system language keys (e.g., HKLM\SYSTEM\CurrentControlSet\Control\Nls\Language) or suspicious processes invoking locale-related APIs (e.g., GetUserDefaultUILanguage, GetSystemDefaultUILanguage, GetKeyboardLayoutList). Defender visibility focuses on anomalous or non-standard processes issuing these queries, especially when run by unknown binaries or scripts.
- AN1562
Processes executing commands to query system locale and language settings, such as 'locale', 'echo $LANG', or parsing environment variables. Suspicious activity is indicated by these commands being run by unusual users, automation scripts, or non-administrative processes.
- AN1563
Execution of commands to query system locale and language settings, such as 'defaults read -g AppleLocale' or 'systemsetup -gettimezone'. Unusual parent processes or execution contexts of these commands may indicate adversarial discovery.
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