X0303 4 2010-02-23 0 0001168195 SOURCEFIRE INC FIRE 0001392156 McDonough Thomas M C/O SOURCEFIRE, INC. 9770 PATUXENT WOODS DRIVE COLUMBIA MD 21046 0 1 0 0 President and COO Common Stock 2010-02-23 4 S 0 3700 22.866 D 111402 I By family trust Common Stock 2010-02-23 4 S 0 1300 23.728 D 110102 I By family trust Common Stock 2010-02-24 4 A 0 13125 0.00 A 80125 D Common Stock 2010-02-24 4 A 0 4375 0.00 A 84500 D Price reflected is the weighted-average sale price for shares sold. The range of sale prices for the transactions reported was $22.53 to $23.38 per share. The reporting person undertakes to provide, upon request by the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. Shares are held by The Revocable Trust of Thomas Michael McDonough u/a July 19, 2005, Thomas M. McDonough, Trustee. The reporting person has voting and investment control with respect to the shares held by the trust. Price reflected is the weighted-average sale price for shares sold. The range of sale prices for the transactions reported was $23.58 to $23.84 per share. The reporting person undertakes to provide, upon request by the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. This grant of restricted stock units was approved by the issuer's compensation committee on February 24, 2010, subject to the reporting person's execution of a restricted stock unit award agreement. Each restricted stock unit represents a contingent right to receive one share of common stock of the issuer. The shares underlying these restricted stock units are eligible for vesting in four equal annual installments beginning on February 24, 2011, the first anniversary of the grant date. Subject to the reporting person's continuous service with the issuer as of such date, the number of shares eligible for vesting on each vesting date will vest based upon the issuer's meeting or exceeding specified annual financial objectives set by the issuer's compensation committee for such year. In the event the financial objectives for a particular year are not achieved, then the shares that otherwise would have vested on such vesting date will vest on February 24, 2015, the fifth anniversary of the grant date, subject to the reporting person's continuous service with the issuer on such date. The shares underlying these restricted stock units vest in four equal annual installments beginning on February 24, 2011, subject to the reporting person's continuous service with the issuer as of the vesting date. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 20, 2009, as amended on August 21, 2009. /s/ Brian F. Leaf, attorney-in-fact 2010-02-25