Internal

Internal network penetration testing focuses on assessing security from the perspective of an attacker who has already gained access to the corporate network. Unlike external assessments that test perimeter defenses, internal tests evaluate how far an attacker can progress once inside - identifying lateral movement opportunities, internal service weaknesses, and privilege escalation paths that could lead to complete infrastructure compromise.

Internal Service Discovery and Enumeration

Corporate networks typically host numerous internal services that are not exposed to the internet but may have weaker security controls than external-facing systems. Network scanning and service enumeration within the internal network reveal databases, administrative panels, monitoring tools, and legacy applications that administrators assumed were safe because they were not publicly accessible. These internal services often run with default credentials, outdated software, or minimal access controls, making them valuable targets during penetration tests.

Command Injection in Internal Applications

Internal web applications - such as network monitoring tools, system administration panels, and DevOps dashboards - frequently incorporate system commands to provide functionality like ping tests, DNS lookups, or log retrieval. These applications are prime targets for command injection because developers often implement less rigorous input validation for internal tools, assuming a trusted user base. Exploiting command injection in internal applications provides a foothold from which attackers can enumerate the system, access sensitive data, and establish persistent access.

Linux Capabilities and Privilege Escalation

Linux capabilities provide a more granular alternative to the traditional root/non-root privilege model. Instead of granting full root access through SUID, specific capabilities can be assigned to binaries - for example, CAP_NET_RAW for packet capture or CAP_DAC_READ_SEARCH for bypassing file read permission checks. However, misconfigured capabilities can create privilege escalation vectors. A binary with CAP_SETUID can change its user ID to root, while CAP_DAC_READ_SEARCH enables reading any file on the system. Understanding Linux capabilities and how they can be abused is an advanced privilege escalation skill essential for thorough internal security assessments.