Description
libc in OpenBSD 6.6 allows authentication bypass via the -schallenge username, as demonstrated by smtpd, ldapd, or radiusd. This is related to gen/auth_subr.c and gen/authenticate.c in libc (and login/login.c and xenocara/app/xenodm/greeter/verify.c).
References
- https://www.openwall.com/lists/oss-security/2019/12/04/5
- https://www.openbsd.org/errata66.html
- [oss-security] 20191204 Re: Authentication vulnerabilities in OpenBSD mailing-list
- [oss-security] 20191204 Authentication vulnerabilities in OpenBSD mailing-list
- 20191205 Authentication vulnerabilities in OpenBSD mailing-list
- http://packetstormsecurity.com/files/155572/Qualys-Security-Advisory-OpenBSD-Authentication-Bypass-Privilege-Escalation.html
- 20191206 Authentication vulnerabilities in OpenBSD mailing-list