Exhibit 31.3
CERTIFICATION
I, Kevin R. Mandia, certify that:
| 1. | I have reviewed this Amendment No. 1 to Annual Report on Form 10-K of Mandiant, Inc.; and |
| 2. | Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report. |
| Date: April 28, 2022 |
/s/ Kevin R. Mandia | |
| Kevin R. Mandia | ||
| Chief Executive Officer | ||
| (Principal Executive Officer) |