openwrt/package/network/services/hostapd/patches/064-0012-EAP-pwd-server-Detect-reflection-attacks.patch
Hauke Mehrtens b463a13881 hostapd: fix multiple security problems
This fixes the following security problems:
* CVE-2019-9494:  cache attack against SAE
* CVE-2019-9495:  cache attack against EAP-pwd
* CVE-2019-9496:  SAE confirm missing state validation in hostapd/AP
* CVE-2019-9497:  EAP-pwd server not checking for reflection attack)
* CVE-2019-9498:  EAP-pwd server missing commit validation for scalar/element
* CVE-2019-9499:  EAP-pwd peer missing commit validation for scalar/element
* CVE-2019-11555: EAP-pwd message reassembly issue with unexpected fragment

Most of these problems are not relevant for normal users, SAE is only
used in ieee80211s mesh mode and EAP-pwd is normally not activated.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
2019-06-21 10:29:23 +02:00

41 lines
1.5 KiB
Diff

From d63edfa90243e9a7de6ae5c275032f2cc79fef95 Mon Sep 17 00:00:00 2001
From: Mathy Vanhoef <mathy.vanhoef@nyu.edu>
Date: Sun, 31 Mar 2019 17:26:01 +0200
Subject: [PATCH 12/14] EAP-pwd server: Detect reflection attacks
When processing an EAP-pwd Commit frame, verify that the peer's scalar
and elliptic curve element differ from the one sent by the server. This
prevents reflection attacks where the adversary reflects the scalar and
element sent by the server. (CVE-2019-9497)
The vulnerability allows an adversary to complete the EAP-pwd handshake
as any user. However, the adversary does not learn the negotiated
session key, meaning the subsequent 4-way handshake would fail. As a
result, this cannot be abused to bypass authentication unless EAP-pwd is
used in non-WLAN cases without any following key exchange that would
require the attacker to learn the MSK.
Signed-off-by: Mathy Vanhoef <mathy.vanhoef@nyu.edu>
---
src/eap_server/eap_server_pwd.c | 9 +++++++++
1 file changed, 9 insertions(+)
--- a/src/eap_server/eap_server_pwd.c
+++ b/src/eap_server/eap_server_pwd.c
@@ -688,6 +688,15 @@ eap_pwd_process_commit_resp(struct eap_s
}
}
+ /* detect reflection attacks */
+ if (crypto_bignum_cmp(data->my_scalar, data->peer_scalar) == 0 ||
+ crypto_ec_point_cmp(data->grp->group, data->my_element,
+ data->peer_element) == 0) {
+ wpa_printf(MSG_INFO,
+ "EAP-PWD (server): detected reflection attack!");
+ goto fin;
+ }
+
/* compute the shared key, k */
if ((crypto_ec_point_mul(data->grp->group, data->grp->pwe,
data->peer_scalar, K) < 0) ||