Internet Explorer SSL Vulnerability :: essays research papers

Abstract mesh Explorers implementation of SSL contains a photograph thatallows for an active, undetected, homophile in the middle attack. No dialogs are shown, no warnings are given.========================================================================DescriptionIn the normal case, the decision maker of a web set might wish to providesecure communication via SSL. To do so, the executive generates a award and has it signed by a Certificate Authority. The generated security system should list the URL of the secure web site in the green Namefield of the Distinguished Name section.The CA verifies that the administrator legitimately owns the URL in the CNfield, signs the certificate, and gives it back. Assuming theadministrator is trying to secure www.thoughtcrime.org, we without delay have thefollowing certificate structureCERT - Issuer VeriSign / melodic theme VeriSign- CERT - Issuer VeriSign / Subject www.thoughtcrime.orgWhen a web browser receives this, it should verify tha t the CN fieldmatches the domain it just connected to, and that its signed using aknown CA certificate. No man in the middle attack is executable because itshould not be possible to substitute a certificate with a reasoned CN and a reasoned signature.However, there is a slightly more complicated scenario. Sometimes it is cheery to delegate signing authority to more localized authorities.In this case, the administrator of www.thoughtcrime.org would get a chainof certificates from the localized authorityIssuer VeriSign / Subject VeriSign- Issuer VeriSign / Subject Intermediate CA- Issuer Intermediate CA / Subject www.thoughtcrime.orgWhen a web browser receives this, it should verify that the CN field ofthe leaf certificate matches the domain it just connected to, that itssigned by the intermediate CA, and that the intermediate CA is signed by aknown CA certificate. Finally, the web browser should also tag that allintermediate certificates have legitimate CA grassroots Constrain ts.You guessed it, Internet Explorer does not check the Basic Constraints.==========================================================================ExploitSo what does this call up? This means that as far as IE is concerned, anyonewith a valid CA-signed certificate for ANY domain can generate a validCA-signed certificate for ANY OTHER domain.As the unscrupulous administrator of www.thoughtcrime.org, I can generatea valid certificate and request a signature from VeriSignCERT - Issuer VeriSign / Subject VeriSign- CERT - Issuer VeriSign / Subject www.thoughtcrime.orgThen I generate a certificate for any domain I want, and sign it using my run-of-the-mine joe-blow CA-signed certificateCERT - Issuer VeriSign / Subject VeriSign- CERT - Issuer VeriSign / Subject www.thoughtcrime.org- CERT - Issuer www.thoughtcrime.org / Subject www.amazon.comSince IE doesnt check the Basic Constraints on the www.thoughtcrime.orgcertificate, it accepts this certificate chain as valid forwww.amazon.com.Anyo ne with any CA-signed certificate (and the corresponding private