This vulnerability occurs when an application sets up its critical internal variables or storage systems using data from untrusted, external sources that an attacker could control.
A secure system should be cautious about trusting any data that originates from outside its own controlled environment. When core application variables or data stores—like configuration flags, security tokens, or internal state trackers—are populated with user-supplied or externally-provided values, attackers can feed them malicious data. This allows them to manipulate the application's logic from the very start, often leading to severe security breaches. In practice, this means developers must ensure that all trusted variables are initialized with hard-coded values, secure internal processes, or rigorously validated data. Relying on external inputs for initialization, even if those inputs are later checked, creates a dangerous window where the system's foundational state is compromised. Always establish critical internal state independently, before processing any untrusted data.
Impact: Modify Application Data
An attacker could gain access to and modify sensitive data or system information.
Strategy: Input Validation
javaphp
/.../*
php