38 CFR § 3.216 - Mandatory disclosure of social security numbers.
Any person who applies for or receives any compensation or pension benefit as defined in §§ 3.3, 3.4, or 3.5 of this part, or a monetary allowance under 38 U.S.C. chapter 18, shall, as a condition for receipt or continued receipt of benefits, furnish the Department of Veterans Affairs upon request with his or her social security number and the social security number of any dependent or beneficiary on whose behalf, or based upon whom, benefits are sought or received. However, no one shall be required to furnish a social security number for any person to whom none has been assigned. Benefits will be terminated if a beneficiary fails to furnish the Department of Veterans Affairs with his or her social security number or the social security number of any dependent or beneficiary on whose behalf, or based upon whom, benefits are sought or received, within 60 days from the date the beneficiary is requested to furnish the social security number.