LIMITED POWER OF ATTORNEY


The undersigned hereby constitutes and appoints each of Terrence J. Schmid, Tram Phi, and Terry
Roelands signing singly, and with full power of substitution, the undersigned's true and lawful
attorney-in-fact to:

	(1)	execute for and on behalf of the undersigned, in the undersigned's capacity as an
officer and/or director of Imperva, Inc. (the "Company"), from time to time the following U.S.
Securities and Exchange Commission ("SEC") forms: (i) Form ID, including any attached
documents, to effect the assignment of codes to the undersigned to be used in the transmission of
information to the SEC using the EDGAR System; (ii) Form 3, Initial Statement of Beneficial
Ownership of Securities, including any attached documents; (iii) Form 4, Statement of Changes in
Beneficial Ownership of Securities, including any attached documents; (iv) Form 5, Annual
Statement of Beneficial Ownership of Securities in accordance with Section 16(a) of the Securities
Exchange Act of 1934, as amended, and the rules thereunder, including any attached documents; (v)
Schedule 13D; and (vi) amendments of each thereof, in accordance with the Securities Exchange Act
of 1934, as amended, and the rules thereunder, including any attached documents;

	(2)	do and perform any and all acts for and on behalf of the undersigned which may be
necessary or desirable to complete and execute any such Form 3, 4 or 5, Schedule 13D or any
amendment(s) thereto, and timely file such form(s) with the SEC and any securities exchange,
national association or similar authority;

	(3)	seek or obtain, as the undersigned's representative and on the undersigned's behalf,
information regarding transactions in the Company's securities from any third party, including
brokers, employee benefit plan administrators and trustees, and the undersigned hereby authorizes
any such person to release any such information to each of the undersigned's attorneys-in-fact
appointed by this Power of Attorney and approves and ratifies any such release of information; and

      (4)	take any other action of any type whatsoever in connection with the foregoing which,
in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required
by, the undersigned, it being understood that the documents executed by such attorney-in-fact on
behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain
such terms and conditions as such attorney-in-fact may approve in such attorney-in-fact's discretion.

	The undersigned hereby grants to each such attorney-in-fact, acting singly, full power and
authority to do and perform any and every act and thing whatsoever requisite, necessary or proper to
be done in the exercise of any of the rights and powers herein granted, as fully to all intents and
purposes as the undersigned might or could do if personally present, with full power of substitution
or revocation, hereby ratifying and confirming all that such attorney-in-fact, or such attorney-in-fact's
substitute or substitutes, shall lawfully do or cause to be done by virtue of this power of attorney and
the rights and powers herein granted.

      The undersigned acknowledges that:

      (1)	the foregoing attorneys-in-fact, in serving in such capacity at the request of the
undersigned, are not assuming, nor is the Company assuming, any of the undersigned's
responsibilities to comply with Section 16 or Regulation 13D-G of the Securities Exchange Act of
1934, as amended, including without limitation (a) any liability of the undersigned for any failure to
comply with such requirements, or (b) any obligation or liability of the undersigned for profit
disgorgement under Section 16(b) of the Securities Exchange Act of 1934, as amended, and this
Power of Attorney does not relieve the undersigned from responsibility for compliance with any such
responsibilities, obligations or liabilities;

      (2)	this Power of Attorney authorizes, but does not require, each such attorney-in-fact to
act in his or her discretion on information provided to such attorney-in-fact without independent
verification of such information; and

      (3)	any documents prepared and/or executed by any such attorney-in-fact on behalf of the
undersigned pursuant to this Power of Attorney will be in such form and will contain such
information and disclosure as such attorney-in-fact, in his or her discretion, deems necessary or
desirable.

      The undersigned hereby agrees to indemnify each attorney-in-fact and the Company from
and against any demand, damage, loss, cost or expense arising from any false or misleading
information provided by the undersigned to the attorney-in fact.

	This Power of Attorney shall remain in full force and effect until the undersigned is no longer
required to file such forms with respect to the undersigned's holdings of and transactions in securities
issued by the Company, unless earlier revoked by the undersigned in a signed writing delivered to the
foregoing attorneys-in-fact.

	IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed
as of October 11, 2011.

							/s/ David N. Strohm
							David N. Strohm