Blast-RADIUS：打破 RADIUS网络设备身份验证、授权和计费的事实标准协议.pdf

1、Blast-RADIUSBreaking Enterprise Network AuthenticationSharon Goldberg1,Miro Haller2,Nadia Heninger2,Mike Milano3,Dan Shumow4,Marc Stevens5,Adam Suhl21Cloudflare,2UC San Diego,3BastionZero,4Microsoft Research,5Centrum Wiskunde&InformaticaBlack Hat Europe 2024;December 12,2024What is RADIUS?Where is i

2、t used?XKCD from 8RADIUS:standard protocol for enterprise networkauthentication.RADIUS is everywhere:RADIUS is.supported by essentially every switch,router,access point,and VPN concentrator productsold in the past twenty-five years.(Alan DeKok 4)Used for backbone routers,non-cable ISP,IoT devices,id

3、entity providers(Okta,Duo),802.1X,enterprise WiFi,eduroam.Miro HallerBHEU 20241/22Blast-RADIUS on a Single SlideHow does RADIUS work?userRADIUS client(router)loginuser/pwRADIUS server(auth DB)Access-Requestuser/pwAccess-AcceptorAccess-Rejectaccess granted!Most RADIUS traffic is sent over UDP.Our pro

4、tocol vulnerability:MITM can change Access-Reject to Access-Accept.Impact:authenticate as any user;accelerate RADIUS/UDP deprecation.Mitigation:responsible disclosure with over 90 vendors(incl.Cisco,Microsoft,.).icons from 6Miro HallerBHEU 20242/22THE RADIUS PROTOCOLRADIUS Packet FormatsAccess-Reque

5、st=Request HeaderRequest NonceAttributes4 bytes16 random bytesUser-Name testPassword Mjg2NzU1zAccess-Accept=Accept HeaderResponse AuthenticatorAttributes4 bytes16 byte“MAC”Reply-Message Welcome test!Exec-Privilege 4Access-Reject=Reject HeaderResponse AuthenticatorAttributes4 bytes16 byte“MAC”Reply-M

6、essage Access deniedMiro HallerBHEU 20243/22Response AuthenticatorGoal:Prevent forgery of packets(e.g.,by MITM attacker).The Response Authenticator from packetResponse HeaderResponse AuthenticatorAttributesis computed asMD5(Response HeaderRequest NonceAttributesShared Secret).copied from responsecop