<PAGE>

                                                                   Exhibit 10.23

                        SUPPLEMENT NO. 2 dated as of October 21, 2000, to the
                  PLEDGE AGREEMENT dated as of June 23, 1999, among ANTEON
                  CORPORATION, a Virginia corporation (the "BORROWER"), AZIMUTH
                  TECHNOLOGIES, INC., a Delaware corporation ("AZIMUTH") and
                  each subsidiary of the Borrower listed on Schedule I hereto
                  (each such subsidiary individually a "SUBSIDIARY PLEDGOR" and
                  collectively, the "SUBSIDIARY PLEDGORS"; the Borrower, Azimuth
                  and Subsidiary Pledgors are referred to collectively herein as
                  the "Pledgors") and MELLON BANK, NA., a national banking
                  association ("MELLON"), as collateral agent (in such capacity,
                  the "COLLATERAL AGENT") for the Secured Parties (as defined in
                  the Credit Agreement referred to below)

      A. Reference is made to (a) the Credit Agreement dated as of June 23, 1999
(as amended, supplemented or otherwise modified from time to time, the "CREDIT
AGREEMENT"), among the Borrower, the lenders from time to time party thereto
(the "LENDERS"), Credit Suisse First Boston, as administrative agent for the
Lenders (in such capacity, the "ADMINISTRATIVE AGENT"), and issuing bank,
Mellon, as Collateral Agent, swingline lender and syndication agent, and
Deutsche Bank A.G., as documentation agent, and (b) the Subsidiary Guarantee
Agreement dated as of June 23, 1999 (as amended, supplemented or otherwise
modified from time to time, the "GUARANTEE AGREEMENT") among the Subsidiary
Pledgors and the Collateral Agent.

      B. Capitalized terms used herein and not otherwise defined herein shall
have the meanings assigned to such terms in the Credit Agreement.

      C. The Pledgors have entered into the Pledge Agreement in order to induce
the Lenders to make Loans and the Issuing Bank to issue Letters of Credit.
Pursuant to Section 5.12 of the Credit Agreement, each Domestic Subsidiary of
the Borrower (other than any Inactive Subsidiary) that was not in existence or
not a Domestic Subsidiary on the date of the Credit Agreement is required to
enter into the Pledge Agreement as a Subsidiary Pledgor upon becoming a Domestic
Subsidiary (or ceasing to be an Inactive Subsidiary) if such Domestic Subsidiary
owns or possesses property of a type that would be considered Collateral under
the Pledge Agreement. Section 24 of the Pledge Agreement provides that such
Domestic Subsidiaries may become Subsidiary Pledgors under the Pledge Agreement
by execution and delivery of an instrument in the form of this Supplement. The
undersigned Domestic Subsidiary (the "NEW PLEDGOR") is executing this Supplement
in accordance with the requirements of the Credit Agreement to become a
Subsidiary Pledgor under the Pledge Agreement in order to induce the Lenders to
make additional Loans and the Issuing Bank to issue additional Letters of Credit
and as consideration for Loans previously made and Letters of Credit previously
issued.

      Accordingly, the Collateral Agent and the New Pledgor agree as follows:

      SECTION 1. In accordance with Section 24 of the Pledge Agreement, the New
Pledgor by its signature below becomes a Pledgor under the Pledge Agreement with
the same force and effect as if originally named therein as a Pledgor and the
New Pledgor hereby agrees (a) to all the terms and provisions of the Pledge
Agreement applicable to it as a Pledgor thereunder and (b) represents and
warrants that the representations and warranties made by it as a Pledgor
thereunder are true and correct on and as of the date hereof. In



<PAGE>

                                                                               2

furtherance of the foregoing, the New Pledgor, as security for the payment and
performance in full of the Obligations (as defined in the Pledge Agreement),
does hereby create and grant to the Collateral Agent, its successors and
assigns, for the benefit of the Secured Parties, their successors and assigns, a
security interest in and lien on all of the New Pledgor's right, title and
interest in and to the Collateral (as defined in the Pledge Agreement) of the
New Pledgor. Each reference to a "SUBSIDIARY PLEDGOR" or a "PLEDGOR" in the
Pledge Agreement shall be deemed to include the New Pledgor. The Pledge
Agreement is hereby incorporated herein by reference.

      SECTION 2. The New Pledgor represents and warrants to the Collateral Agent
and the other Secured Parties that this Supplement has been duly authorized,
executed and delivered by it and constitutes its legal, valid and binding
obligation, enforceable against it in accordance with its terms.

      SECTION 3. This Supplement may be executed in counterparts, each of which
shall constitute an original, but all of which when taken together shall
constitute a single contract. This Supplement shall became effective when the
Collateral Agent shall have received counterparts of this Supplement that, when
taken together, bear the signatures of the New Pledgor and the Collateral Agent.
Delivery of an executed signature page to this Supplement by facsimile
transmission shall be as effective as delivery of a manually signed counterpart
of this Supplement.

      SECTION 4. The New Pledgor hereby represents and warrants that set forth
on Schedule I attached hereto is a true and correct schedule of all its Pledged
Securities.

      SECTION 5. Except as expressly supplemented hereby, the Pledge Agreement
shall remain in full force and effect.

      SECTION 6. THIS SUPPLEMENT SHALL BE GOVERNED BY, AND CONSTRUED IN
ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

      SECTION 7. In case any one or more of the provisions contained in this
Supplement should be held invalid, illegal or unenforceable in any respect,
neither party hereto shall be required to comply with such provision for so long
as such provision is held to be invalid, illegal or unenforceable, but the
validity, legality and enforceability of the remaining provisions contained
herein and in the Pledge Agreement shall not in any way be affected or impaired.
The parties hereto shall endeavor in good-faith negotiations to replace the
invalid, illegal or unenforceable provisions with valid provisions the economic
effect of which comes as close as possible to that of the invalid, illegal or
unenforceable provisions.

      SECITON 8. All communications and notices hereunder shall be in writing
and given as provided in Section 16 of the Pledge Agreement. All communications
and notices hereunder to the New Pledgor shall be given to it in care of the
Borrower.

      SECTION 9. The New Pledgor agrees to reimburse the Collateral Agent for
its reasonable out-of-pocket expenses in connection with this Supplement,
including the reasonable fees, other charges and disbursements of counsel for
the Collateral Agent.


<PAGE>

                                                                               3


      IN WITNESS WHEREOF, the New Pledgor and the Collateral Agent have duly
executed this Supplement to the Pledge Agreement as of the day and year first
above written.

                                      SHERIKON, INC., as a New Pledgor,


                                      by: /s/ Carton B. Crenshaw
                                         ---------------------------------------
                                         Name: Carton B. Crenshaw
                                         Title: Vice President
                                         Address: 14500 Avion Pkwy, Suite 200,
                                         Chantilly, VA 20151

                                      SOUTH TEXAS SHIP REPAIR, INC., as a New
                                      Pledgor,

                                      by: /s/ Carton B. Crenshaw
                                         ---------------------------------------
                                         Name: Carton B. Crenshaw
                                         Title: Vice President
                                         Address: Redfish Bay Terminal, Ocean
                                         Drive at Beasley, Aransas Pass, TX
                                         78336

                                      SHERIKON SPACE SYSTEMS, INC., as a New
                                      Pledgor,

                                      by: /s/ Carton B. Crenshaw
                                         ---------------------------------------
                                         Name: Carton B. Crenshaw
                                         Title: Vice President
                                         Address: 12249 Science Drive, Suite
                                         106, Orlando, FL 32826

                                      MELLON BANK, N.A., as Collateral Agent

                                      by:
                                         ---------------------------------------
                                         Name:
                                         Title:


<PAGE>

                                                                               3


      IN WITNESS WHEREOF, the New Pledgor and the Collateral Agent have duly
executed this Supplement to the Pledge Agreement as of the day and year first
above written.


                                      SHERIKON, INC., as a New Pledgor,


                                      by:
                                         ---------------------------------------
                                         Name:
                                         Title:
                                         Address: 14500 Avion Pkwy, Suite 200,
                                         Chantilly, VA 20151


                                      SOUTH TEXAS SHIP REPAIR, INC., as a
                                      New Pledgor,


                                      by:
                                         ---------------------------------------
                                         Name:
                                         Title:
                                         Address: Redfish Bay Terminal, Ocean
                                         Drive at Beasley, Aransas Pass, TX
                                         78336


                                      SHERIKON SPACE SYSTEMS, INC., as a
                                      New Pledgor,


                                      by:
                                         ---------------------------------------
                                         Name:
                                         Title:
                                         Address: 12249 Science Drive, Suite
                                         106, Orlando, FL 32826


                                      MELLON BANK, N.A., as Collateral Agent,


                                      by: /s/ Leslie A. Grizzard
                                         ---------------------------------------
                                         Name: Leslie A. Grizzard
                                         Title: Vice President



<PAGE>

                                                                   Schedule I to
                                                                Supplement No. 2
                                                         to the Pledge Agreement


                      PLEDGED SECURITIES OF THE NEW PLEDGOR

                                EQUITY INTERESTS

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------
                         Numbers
                           of                               Number and       Percentage of
      Issuer           Certificate     Registered Owner   Class of Shares       Shares
---------------------------------------------------------------------------------------------
<S>                         <C>       <C>                    <C>                  <C>
Sherikon, Inc.              9         Anteon Corporation        970               100%
---------------------------------------------------------------------------------------------
Sherikon Space              1         Sherikon, Inc.         10,000               100%
Systems, Inc.
---------------------------------------------------------------------------------------------
Sherikon Texas              1         Sherikon , Inc.         1,000               100%
Ship Repair, Inc.
---------------------------------------------------------------------------------------------
</TABLE>


                                DEBT SECURITIES

<TABLE>
<CAPTION>

---------------------------------------------------------------------------------------------
        Issuer             Principal Amount         Date of Note          Maturity Date
---------------------------------------------------------------------------------------------
<S>                        <C>                      <C>                   <C>

---------------------------------------------------------------------------------------------

---------------------------------------------------------------------------------------------
</TABLE>