Infiltration
Privilege escalation normally occurs deep into the stages of an attack. This means that the attacker will have already done reconnaissance and successfully compromised a system, thereby gaining entry. After this, the attacker will have traversed the compromised system or network through lateral movement and identified all the systems and devices of interest.
In this phase, the attacker wants to have a strong grip on the system. The attacker may have compromised a low-level account and will, therefore, be looking for an account with higher privileges, in order to study the system further or get ready to give the final blow. Privilege escalation is not a simple phase, as it will at times require the attacker to use a combination of skills and tools in order to heighten the privileges. There are generally two classifications of privilege escalation: horizontal and vertical privilege escalation.
Figure 1: Privilege escalation can be done horizontally as well as vertically...