Project Overview

Following the discovery of a critical bug in a PHP project under the client’s operation, we conducted a cross-project review to verify whether similar issues might exist in other PHP projects. Based on the investigation items, source patterns, and function list provided by the client, our team thoroughly examined the PHP source code, classified the impact levels, and compiled the findings into an investigation report.

Technology Stack & Tools Used

• Programming Language: PHP
• Task Management Tool: Excel
• Communication Tool: Redmine

Client Challenges

• Risk of propagation across projects
  It could not be ruled out that the identified critical bug might propagate to other PHP projects using the same language or similar patterns. Legacy components and external integration points were of particular concern; without precise scoping of impact, operational risk would remain.
• Insufficient proof of safety
  The remaining projects lacked objective evidence and traceable records to demonstrate safety. Review perspectives, procedures, and decision criteria were not unified, leading to inconsistent evaluations and weaker accountability.
• Standardization of testing and reporting
  Investigation viewpoints, check patterns, and target scope varied by project, reducing reproducibility. Classification axes and prioritization were also inconsistent, increasing the time required to translate results into remediation plans.

Client Requirements

• Detailed source code review (Content)
  Perform an in-depth review of PHP source code strictly in line with the provided investigation items, recording item-by-item results to avoid omissions.
• Adherence to investigation items (Content)
  Proceed based on the client-defined source patterns and function list; maintain consistency by staying within the prescribed viewpoints.
• Impact classification (Content)
  Organize findings by impact level and apply the classification consistently so results are comparable on the same axis.
• Consolidation of analysis results (Content)
  Structure the outcomes into a non-duplicative catalog and summarize key points for downstream decision-making and easier reference.
• Submission of the report (Content)
  Upon completion, submit a report with clear conclusions and supporting rationale, written concisely and structured for practical use in decisions.

Our Proposal & Approach

• Information gathering and scope definition
  Received the function list and patterns; clarified the scope across projects/modules/PHP source. Early alignment on assumptions and investigation viewpoints minimized divergence.
• Source code investigation
  Performed cross-searches using the provided lists; recorded presence, locations, counts, and related implementations, noting the decision basis to compare recurrence potential.
• Client collaboration and timely alignment
  Confirmed any discrepancies between actual code and provided information; updated assumptions during the investigation to reduce false positives/negatives, and secured agreement on key points via interim reports.
• Result consolidation and reporting
  Classified by impact level and clarified remediation priority; produced a comprehensive report covering targets, evidence, and judgments to support remediation planning.