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Bug#905762: stretch-pu: package wpa/2:2.4-1+deb9u2



Package: release.debian.org
Severity: normal
Tags: stretch
User: release.debian.org@packages.debian.org
Usertags: pu

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Hash: SHA256

Hi,

I would like to fix CVE-2018-14526 (#905739) in stable:

CVE-2018-14526[0]:
| An issue was discovered in rsn_supp/wpa.c in wpa_supplicant 2.0
| through 2.6. Under certain conditions, the integrity of EAPOL-Key
| messages is not checked, leading to a decryption oracle. An attacker
| within range of the Access Point and client can abuse the
| vulnerability to recover sensitive information.

This is a low priority security issue, and doesn't require a DSA.

[0] https://security-tracker.debian.org/tracker/CVE-2018-14526

- -- 
Cheers,
  Andrej

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diff -Nru wpa-2.4/debian/changelog wpa-2.4/debian/changelog
--- wpa-2.4/debian/changelog	2017-10-14 14:18:32.000000000 +0200
+++ wpa-2.4/debian/changelog	2018-08-09 09:23:49.000000000 +0200
@@ -1,3 +1,11 @@
+wpa (2:2.4-1+deb9u2) stretch; urgency=high
+
+  * SECURITY UPDATE:
+    - CVE-2018-14526: Ignore unauthenticated encrypted EAPOL-Key data
+      (Closes: #905739)
+
+ -- Andrej Shadura <andrewsh@debian.org>  Thu, 09 Aug 2018 09:23:49 +0200
+
 wpa (2:2.4-1+deb9u1) stretch-security; urgency=high
 
   * Non-maintainer upload by the Security Team.
diff -Nru wpa-2.4/debian/patches/CVE-2018-14526/rebased-v2.6-0001-WPA-Ignore-unauthenticated-encrypted-EAPOL-Key-data.patch wpa-2.4/debian/patches/CVE-2018-14526/rebased-v2.6-0001-WPA-Ignore-unauthenticated-encrypted-EAPOL-Key-data.patch
--- wpa-2.4/debian/patches/CVE-2018-14526/rebased-v2.6-0001-WPA-Ignore-unauthenticated-encrypted-EAPOL-Key-data.patch	1970-01-01 01:00:00.000000000 +0100
+++ wpa-2.4/debian/patches/CVE-2018-14526/rebased-v2.6-0001-WPA-Ignore-unauthenticated-encrypted-EAPOL-Key-data.patch	2018-08-09 09:17:22.000000000 +0200
@@ -0,0 +1,44 @@
+From 3e34cfdff6b192fe337c6fb3f487f73e96582961 Mon Sep 17 00:00:00 2001
+From: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be>
+Date: Sun, 15 Jul 2018 01:25:53 +0200
+Subject: [PATCH] WPA: Ignore unauthenticated encrypted EAPOL-Key data
+
+Ignore unauthenticated encrypted EAPOL-Key data in supplicant
+processing. When using WPA2, these are frames that have the Encrypted
+flag set, but not the MIC flag.
+
+When using WPA2, EAPOL-Key frames that had the Encrypted flag set but
+not the MIC flag, had their data field decrypted without first verifying
+the MIC. In case the data field was encrypted using RC4 (i.e., when
+negotiating TKIP as the pairwise cipher), this meant that
+unauthenticated but decrypted data would then be processed. An adversary
+could abuse this as a decryption oracle to recover sensitive information
+in the data field of EAPOL-Key messages (e.g., the group key).
+(CVE-2018-14526)
+
+Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be>
+---
+ src/rsn_supp/wpa.c | 11 +++++++++++
+ 1 file changed, 11 insertions(+)
+
+diff -upr wpa_supplicant-2.6.orig/src/rsn_supp/wpa.c wpa_supplicant-2.6/src/rsn_supp/wpa.c
+--- wpa_supplicant-2.6.orig/src/rsn_supp/wpa.c	2016-10-02 21:51:11.000000000 +0300
++++ wpa_supplicant-2.6/src/rsn_supp/wpa.c	2018-08-08 16:55:11.506831029 +0300
+@@ -2016,6 +2016,17 @@ int wpa_sm_rx_eapol(struct wpa_sm *sm, c
+ 
+ 	if ((sm->proto == WPA_PROTO_RSN || sm->proto == WPA_PROTO_OSEN) &&
+ 	    (key_info & WPA_KEY_INFO_ENCR_KEY_DATA)) {
++		/*
++		 * Only decrypt the Key Data field if the frame's authenticity
++		 * was verified. When using AES-SIV (FILS), the MIC flag is not
++		 * set, so this check should only be performed if mic_len != 0
++		 * which is the case in this code branch.
++		 */
++		if (!(key_info & WPA_KEY_INFO_MIC)) {
++			wpa_msg(sm->ctx->msg_ctx, MSG_WARNING,
++				"WPA: Ignore EAPOL-Key with encrypted but unauthenticated data");
++			goto out;
++		}
+ 		if (wpa_supplicant_decrypt_key_data(sm, key, ver, key_data,
+ 						    &key_data_len))
+ 			goto out;
diff -Nru wpa-2.4/debian/patches/series wpa-2.4/debian/patches/series
--- wpa-2.4/debian/patches/series	2017-10-14 14:16:40.000000000 +0200
+++ wpa-2.4/debian/patches/series	2018-08-09 09:17:41.000000000 +0200
@@ -45,3 +45,4 @@
 2017-1/0010-WNM-Ignore-WNM-Sleep-Mode-Response-without-pending-r.patch
 2017-1/0011-FT-Do-not-allow-multiple-Reassociation-Response-fram.patch
 2017-1/0012-TDLS-Ignore-incoming-TDLS-Setup-Response-retries.patch
+CVE-2018-14526/rebased-v2.6-0001-WPA-Ignore-unauthenticated-encrypted-EAPOL-Key-data.patch

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