-----BEGIN PGP SIGNED MESSAGE----- =============================================================================== Security Advisory CERT-NL =============================================================================== Author/Source : Rene Ritzen Index : S-97-81 Distribution : World Page : 1 Classification: External Version: 1 Subject : Sanitizing User-Supplied Data in CGI Scripts Date :13-nov-97 =============================================================================== By courtesy of CERT Coordination Center we received the following information. CERT Coordination Center advisory CA-97.25 - Sanitizing User-Supplied Data in CGI Scripts. The CERT Coordination Center has received reports and seen mailing list discussions of a problem with some CGI scripts, which allow an attacker to execute arbitrary commands on a WWW server under the effective user-id of the server process. The problem lies in how the scripts are written, NOT in the scripting languages themselves. CERT-NL urges you to check all CGI scripts that are available via th World Wide Web services at your site and asure that they sanitize user-supplied data. A tech tip on how to do this is given in Section III. All CERT Coordination Center advisories are mirrored by CERT-NL. The specific URL for this case is: ADVISORIES ARE REGULARLY UPDATED BY CERT COORDINATION CENTER. Therefore we advise you to check on our mirror regularly - you can automate this process using the CERT-NL notifier service. More information about the CERT-NL mirror and notifier services is contained in News items N-95-01 (notifier) and N-95-02 (CERT mirror), both present on ============================================================================== CERT-NL is the Computer Emergency Response Team for SURFnet customers. SURFnet is the Dutch network for educational, research and related institutes. CERT-NL is a member of the Forum of Incident Response and Security Teams (FIRST). All CERT-NL material is available under: http://www.surfnet.nl/surfnet/security/cert-nl.html ftp://ftp.surfnet.nl/surfnet/net-security In case of computer or network security problems please contact your local CERT/security-team or CERT-NL (if your institute is NOT a SURFnet customer please address the appropriate (local) CERT/security-team). CERT-NL is one/two hour(s) ahead of UTC (GMT) in winter/summer, i.e. UTC+0100 in winter and UTC+0200 in summer (DST). Email: cert-nl@surfnet.nl ATTENDED REGULARLY ALL DAYS Phone: +31 302 305 305 BUSINESS HOURS ONLY Fax: +31 302 305 329 BUSINESS HOURS ONLY Snailmail: SURFnet bv Attn. CERT-NL P.O. Box 19035 NL - 3501 DA UTRECHT The Netherlands NOODGEVALLEN: 06 52 87 92 82 ALTIJD BEREIKBAAR EMERGENCIES : +31 6 52 87 92 82 ATTENDED AT ALL TIMES CERT-NL'S EMERGENCY PHONENUMBER IS ONLY TO BE USED IN CASE OF EMERGENCIES: THE SURFNET HELPDESK OPERATING THE EMERGENCY NUMBER HAS A *FIXED* PROCEDURE FOR DEALING WITH YOUR ALERT AND WILL IN REGULAR CASES RELAY IT TO CERT-NL IN AN APPROPRIATE MANNER. CERT-NL WILL THEN CONTACT YOU. ============================================================================== -----BEGIN PGP SIGNATURE----- Version: 2.6.3i Charset: cp850 iQCVAwUBNHAOEUU5nQkWIq1FAQGucQP/ZbqZhxy6Y54dR7eg30218Xi3qwcQEHs1 VI3vBBUQ8Xis9zIR5eP+7G+o7FeAKrSDOPjGDxduP7Sc2i1GiPf8+LjFnyDFe8Wu 4xkxiwqBsycPNKWw603vWPvF2n2d7caeECVcC/KKMmA0jsIZWg0MqLijTKiiQCWX xlnv0EyTXbY= =nntL -----END PGP SIGNATURE-----