Race Condition Affecting openssh package, versions <7.7_p1-r4

Note: Versions mentioned in the description apply only to the upstream openssh package and not the openssh package as distributed by Alpine. See How to fix? for Alpine:3.12 relevant fixed versions and status.

OpenSSH through 7.7 is prone to a user enumeration vulnerability due to not delaying bailout for an invalid authenticating user until after the packet containing the request has been fully parsed, related to auth2-gss.c, auth2-hostbased.c, and auth2-pubkey.c.

• https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2018-0011
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-15473
• https://bugs.debian.org/906236
• https://www.debian.org/security/2018/dsa-4280
• https://lists.debian.org/debian-lts-announce/2018/08/msg00022.html
• https://security-tracker.debian.org/tracker/CVE-2018-15473
• https://www.exploit-db.com/exploits/45210/
• https://www.exploit-db.com/exploits/45233/
• https://www.exploit-db.com/exploits/45939/
• https://security.gentoo.org/glsa/201810-03
• https://github.com/openbsd/src/commit/779974d35b4859c07bc3cb8a12c74b43b0a7d1e0
• https://www.oracle.com/security-alerts/cpujan2020.html
• https://security.netapp.com/advisory/ntap-20181101-0001/
• http://www.openwall.com/lists/oss-security/2018/08/15/5
• https://access.redhat.com/errata/RHSA-2019:0711
• https://access.redhat.com/errata/RHSA-2019:2143
• http://www.securityfocus.com/bid/105140
• http://www.securitytracker.com/id/1041487
• http://people.ubuntu.com/~ubuntu-security/cve/CVE-2018-15473
• https://usn.ubuntu.com/3809-1/
• https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
• https://www.exploit-db.com/exploits/45233