[Sec3043] - validate origin timestamps on bad MACs, too. stenn@ntp.org

bk: 5747dd0fk9FN_tD9dhCQXHL8TNSdWw

diff --git a/ChangeLog b/ChangeLog
index 05fd404d5da0b9dee272d8b80211781f7df0b2fc..4fdad3d64b19c792e64ece9686c6db105b5679d8 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,8 +2,9 @@
 
 * [Sec 3042] Broadcast Interleave.  HStenn.
 * [Sec 3043] Autokey association reset.  perlinger@ntp.org, stenn@ntp.org
-  - fixes [Sec 3044] (partially) and [Sec 3045], too.
+  - validate origin timestamps on bad MACs, too.  stenn@ntp.org
 * [Sec 3044] Spoofed server packets are partially processed.  HStenn.
+* [Sec 3045] Bad authentication demobilizes ephemeral associations. JPerlinger.
 * [Sec 3046] CRYPTO_NAK crash.  stenn@ntp.org
 * [Bug 3038] NTP fails to build in VS2015. perlinger@ntp.org
   - provide build environment

diff --git a/NEWS b/NEWS
index 17aef607114f7ccc71083779e20802d95c02edc2..6d841198aa12745f91d96e2bd973b0965cb003d8 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -10,7 +10,7 @@ following 1 high- and 4 low-severity vulnerabilities"
 
 * CRYPTO_NAK crash
    Date Resolved: 02 June 2016; Dev (4.3.93) 02 June 2016
-   References: Sec 3046 / CVE-2016-4957 / VU#BBBBB
+   References: Sec 3046 / CVE-2016-4957 / VU#321640
    Affects: ntp-4.2.8p7, and ntp-4.3.92.
    CVSS2: HIGH 7.8 (AV:N/AC:L/Au:N/C:N/I:N/A:C)
    CVSS3: HIGH 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
@@ -28,7 +28,7 @@ following 1 high- and 4 low-severity vulnerabilities"
 
 * Bad authentication demobilizes ephemeral associations
    Date Resolved: 02 June 2016; Dev (4.3.93) 02 June 2016
-   References: Sec 3045 / CVE-2016-4953
+   References: Sec 3045 / CVE-2016-4953 / VU#321640
    Affects: ntp-4, up to but not including ntp-4.2.8p8, and
        ntp-4.3.0 up to, but not including ntp-4.3.93.
    CVSS2: LOW 2.6 (AV:N/AC:H/Au:N/C:N/I:N/A:P)
@@ -46,7 +46,7 @@ following 1 high- and 4 low-severity vulnerabilities"
 
 * Processing spoofed server packets
    Date Resolved: 02 June 2016; Dev (4.3.93) 02 June 2016
-   References: Sec 3044 / CVE-2016-4954
+   References: Sec 3044 / CVE-2016-4954 / VU#321640
    Affects: ntp-4, up to but not including ntp-4.2.8p8, and
        ntp-4.3.0 up to, but not including ntp-4.3.93.
    CVSS2: LOW 2.6 (AV:N/AC:H/Au:N/C:N/I:N/A:P)
@@ -60,20 +60,20 @@ following 1 high- and 4 low-severity vulnerabilities"
        Upgrade to 4.2.8p8, or later, from the NTP Project Download Page
            or the NTP Public Services Project Download Page
        Properly monitor your ntpd instances. 
-   Credit: This weakness was discovered by Miroslav Lichvar of Red Hat. 
+   Credit: This weakness was discovered by Jakub Prokes of Red Hat. 
 
 * Autokey association reset
    Date Resolved: 02 June 2016; Dev (4.3.93) 02 June 2016
-   References: Sec 3043 / CVE-2016-4955
+   References: Sec 3043 / CVE-2016-4955 / VU#321640
    Affects: ntp-4, up to but not including ntp-4.2.8p8, and
        ntp-4.3.0 up to, but not including ntp-4.3.93.
    CVSS2: LOW 2.6 (AV:N/AC:H/Au:N/C:N/I:N/A:P)
    CVSS3: LOW 3.7 CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
    Summary: An attacker who is able to spoof a packet with a correct
        origin timestamp before the expected response packet arrives at
-       the target machine can send a CRYPTO_NAK and cause the
-       association's peer variables to be cleared. If this can be done
-       often enough, it will prevent that association from working.
+       the target machine can send a CRYPTO_NAK or a bad MAC and cause
+       the association's peer variables to be cleared. If this can be
+       done often enough, it will prevent that association from working.
    Mitigation:
        Implement BCP-38.
        Upgrade to 4.2.8p8, or later, from the NTP Project Download Page
@@ -83,7 +83,7 @@ following 1 high- and 4 low-severity vulnerabilities"
  
 * Broadcast interleave
    Date Resolved: 02 June 2016; Dev (4.3.93) 02 June 2016
-   References: Sec 3042 / CVE-2016-4956
+   References: Sec 3042 / CVE-2016-4956 / VU#321640
    Affects: ntp-4, up to but not including ntp-4.2.8p8, and
        ntp-4.3.0 up to, but not including ntp-4.3.93.
    CVSS2: LOW 2.6 (AV:N/AC:H/Au:N/C:N/I:N/A:P)

diff --git a/ntpd/ntp_proto.c b/ntpd/ntp_proto.c
index 7809fb4a3454598be86357db57a88232584d1c3e..513b99f683e3db8935e283aadbc5f51ea3f916e5 100644 (file)
--- a/ntpd/ntp_proto.c
+++ b/ntpd/ntp_proto.c
@@ -1682,8 +1682,9 @@ receive(
        /*
         * Check for valid nonzero timestamp fields.
         */
-       } else if (L_ISZERO(&p_org) || L_ISZERO(&p_rec) ||
-           L_ISZERO(&peer->dst)) {
+       } else if (   L_ISZERO(&p_org)
+                  || L_ISZERO(&p_rec)
+                  || L_ISZERO(&peer->dst)) {
                peer->flash |= TEST3;           /* unsynch */
 
        /*
@@ -1699,6 +1700,8 @@ receive(
                return; /* Bogus packet, we are done */
        }
 
+       /**/
+
        /*
         * If this is a crypto_NAK, the server cannot authenticate a
         * client packet. The server might have just changed keys. Clear
@@ -1715,8 +1718,9 @@ receive(
                        return;
                }
 #ifdef AUTOKEY
-               if (peer->crypto)
+               if (peer->crypto) {
                        peer_clear(peer, "AUTH");
+               }
 #endif /* AUTOKEY */
                return;
 
@@ -1730,21 +1734,30 @@ receive(
         */
        } else if (!AUTH(peer->keyid || has_mac ||
                         (restrict_mask & RES_DONTTRUST), is_authentic)) {
+
+               if (peer->flash & PKT_TEST_MASK) {
+                       msyslog(LOG_INFO,
+                               "receive: Bad auth in packet with bad timestamps from %s denied - spoof?",
+                               ntoa(&peer->srcadr));
+                       return;
+               }
+
                report_event(PEVNT_AUTH, peer, "digest");
                peer->flash |= TEST5;           /* bad auth */
                peer->badauth++;
                if (   has_mac
-                   && (hismode == MODE_ACTIVE || hismode == MODE_PASSIVE))
+                   && (   hismode == MODE_ACTIVE
+                       || hismode == MODE_PASSIVE))
                        fast_xmit(rbufp, MODE_ACTIVE, 0, restrict_mask);
                if (peer->flags & FLAG_PREEMPT) {
                        if (unpeer_digest_early) {
                                unpeer(peer);
                        }
-                       return;
                }
 #ifdef AUTOKEY
-               if (peer_clear_digest_early && peer->crypto)
+               else if (peer_clear_digest_early && peer->crypto) {
                        peer_clear(peer, "AUTH");
+               }
 #endif /* AUTOKEY */
                return;
        }