NULL pointer dereference in hostapd

1) NULL pointer dereference

EUVDB-ID: #VU31083

Risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-11555

CWE-ID: CWE-476 - NULL Pointer Dereference

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error in hostapd (EAP server) before 2.8 and wpa_supplicant (EAP peer) before 2.8 does not validate fragmentation reassembly state properly for a case where an unexpected fragment could be received. This could result in process termination due to a NULL pointer dereference (denial of service). This affects eap_server/eap_server_pwd.c and eap_peer/eap_pwd.c. A remote attacker can perform a denial of service (DoS) attack.

Mitigation

Update to version 2.8.

Vulnerable software versions

hostapd: 2.0 - 2.7

CPE2.3

• cpe:2.3:a:jouni_malinen:hostapd:2.0:*:*:*:*:*:*:
• cpe:2.3:a:jouni_malinen:hostapd:2.1:*:*:*:*:*:*:
• cpe:2.3:a:jouni_malinen:hostapd:2.2:*:*:*:*:*:*:

External links

http://www.openwall.com/lists/oss-security/2019/04/26/1
http://lists.debian.org/debian-lts-announce/2019/07/msg00030.html
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/5T7G763UECWR7FQXOJVL67PW7C5A3SA4/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DJKZHAT5KPUN26JL77EUH563GAH5XZ5C/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IQ6P2GI5GSXRNLNIUNPARFZQVDEIGVZD/
http://seclists.org/bugtraq/2019/May/40
http://seclists.org/bugtraq/2019/May/64
http://security.FreeBSD.org/advisories/FreeBSD-SA-19:03.wpa.asc
http://security.gentoo.org/glsa/201908-25
http://usn.ubuntu.com/3969-1/
http://usn.ubuntu.com/3969-2/
http://w1.fi/security/2019-5/
http://w1.fi/security/2019-5/eap-pwd-message-reassembly-issue-with-unexpected-fragment.txt
http://www.debian.org/security/2019/dsa-4450
http://www.openwall.com/lists/oss-security/2019/04/18/6

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.