Final answer:
The audit procedure involving an attorney's letter indicating no lawsuits is known as confirmation, which verifies information through a direct response from a third party.
Step-by-step explanation:
The audit procedure that involves obtaining a letter from the entity's attorney indicating that there were no lawsuits in progress against the entity is known as confirmation. This procedure is used to verify information or existing conditions and involves the receipt of a direct written response from a third party verifying the accuracy of information that was requested by the auditor. In this case, the attorney's letter would serve as a legal confirmation regarding the absence of ongoing lawsuits, which would be pertinent to the financial statement assertions related to contingencies and commitments.