T1546.017: Udev Rules
Udev Rules (T1546.017) é uma técnica catalogada no MITRE ATT&CK Enterprise usada como referência para mapear comportamento adversário em auditorias de segurança.
Contexto para AppSec
Em uma auditoria de AppSec, Udev Rules deve ser usada para revisar caminhos em que código, configuração, dependências ou infraestrutura podem viabilizar o comportamento descrito pela MITRE. No ATT&CK, ela aparece em Persistence e Privilege Escalation. As plataformas mapeadas pela MITRE incluem Linux. No Vigly, esse contexto ajuda a conectar evidências do repositório com priorização e remediação.
Descrição oficial original do MITRE ATT&CK
Adversaries may maintain persistence through executing malicious content triggered using udev rules. Udev is the Linux kernel device manager that dynamically manages device nodes, handles access to pseudo-device files in the /dev directory, and responds to hardware events, such as when external devices like hard drives or keyboards are plugged in or removed. Udev uses rule files with match keys to specify the conditions a hardware event must meet and action keys to define the actions that should follow. Root permissions are required to create, modify, or delete rule files located in /etc/udev/rules.d/, /run/udev/rules.d/, /usr/lib/udev/rules.d/, /usr/local/lib/udev/rules.d/, and /lib/udev/rules.d/. Rule priority is determined by both directory and by the digit prefix in the rule filename. Adversaries may abuse the udev subsystem by adding or modifying rules in udev rule files to execute malicious content. For example, an adversary may configure a rule to execute their binary each time the pseudo-device file, such as /dev/random, is accessed by an application. Although udev is limited to running short tasks and is restricted by systemd-udevd's sandbox (blocking network and filesystem access), attackers may use scripting commands under the action key RUN+= to detach and run the malicious content’s process in the background to bypass these controls.
Como o Vigly audita a técnica Udev Rules automaticamente na sua pipeline
O Vigly cruza sinais de SAST, modelagem de ameaças, regras de negócio e evidências do repositório para priorizar riscos reais antes que eles cheguem à produção.
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