UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 9)(1)

NETWORK-1 SECURITY SOLUTIONS, INC.

(Name of Issuer)

Common Stock, $0.01 Par Value Per Share

(Title of Class of Securities)

       64121N109        

(CUSIP Number)

Woodland Partners

68 Wheatley Road

Brookville, NY 11545

Telephone: (516) 626-3070

With a copy to:

Michael R. Reiner, Esq.

Breslow & Walker, LLP

767 Third Avenue

New York, New York 10017

Telephone: (212) 832-1930

(Name, Address and Telephone Number of Person Authorized

to Receive Notices and Communications)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box: o

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule13d-7 for other parties to whom copies are to be sent.

(Continued on following page(s))

(1) The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

This statement, dated October 4, 2013, constitutes Amendment No. 9 to the Schedule 13D, dated November 12, 1998, regarding the reporting persons’ ownership of certain securities of Network-1 Security Solutions, Inc. All capitalized terms used herein and otherwise undefined shall have the meanings ascribed in the Schedule.

Item 5 is hereby amended and restated as follows:

(a)     The following list sets forth the aggregate number and percentage (based on 26,047,683 shares of Common Stock outstanding as reported in the Issuer’s Form 10-Q/A for the quarter ended June 30, 2013), of outstanding shares of Common Stock owned beneficially by each reporting person named in Item 2, as of October 4, 2013:

(b)     Barry Rubenstein, by virtue of being a general partner of Woodland Venture, Seneca, Woodland Partners and Brookwood, and the husband of Marilyn Rubenstein, may be deemed to have shared power to vote and to dispose of 1,654,382 shares of Common Stock, representing approximately 6.4% of the outstanding Common Stock. Barry Rubenstein has sole power to vote and to dispose of 160,011 shares of Common Stock (including shares issuable upon the exercise of the August 2009 Option), representing approximately 0.6% of the outstanding Common Stock.

Irwin Lieber has sole power to vote and to dispose of 481,600 shares of Common Stock (including shares issuable upon the exercise of the August 2009 Option), representing approximately 1.8% of the outstanding Common Stock.

Seth Lieber has sole power to vote and to dispose of 34,136 shares of Common Stock, representing approximately 0.1% of the outstanding Common Stock.

Jonathan Lieber has sole power to vote and to dispose of 32,584 shares of Common Stock, representing approximately 0.1% of the outstanding Common Stock.

Woodland Venture has sole power to vote and to dispose of 669,224 shares of Common Stock, representing approximately 2.6% of the outstanding Common Stock.

Seneca has sole power to vote and to dispose of 479,983 shares of Common Stock, representing approximately 1.8% of the outstanding Common Stock.

Marilyn Rubenstein has sole power to vote and to dispose of 1,049 shares of Common Stock, representing approximately 0.004% of the outstanding Common Stock, and by virtue of being an officer of Services and a general partner of Woodland Partners and Brookwood, may be deemed to have shared power to vote and to dispose of 1,653,333 shares of Common Stock, representing approximately 6.3% of the outstanding Common Stock.

Services by virtue of being a general partner of Woodland Venture and Seneca, may be deemed to have shared power to vote and to dispose of 1,149,207 shares of Common Stock, representing approximately 4.4% of the outstanding Common Stock.

Woodland Partners has sole power to vote and to dispose of 309,316 shares of Common Stock, representing approximately 1.2% of the outstanding Common Stock.

Brookwood has sole power to vote and to dispose of 194,810 shares of Common Stock, representing approximately 0.7% of the outstanding Common Stock.

(c)     The following table sets forth the transactions in the securities of the Issuer by the Reporting Persons identified in Item 2 of this Schedule 13D which were effected during the prior sixty days from October 4, 2013:

(d)     No other person has the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of such securities.

(e)     On October 4, 2013, Applegreen Partners ceased to be the beneficial owner of more than five percent (5%) of the Common Stock.

SIGNATURE

After reasonable inquiry and to the best of his/her/its knowledge and belief, each of the undersigned hereby certifies that the information set forth in this Schedule is true, complete and correct.

Dated: October 9, 2013