Denial of service in Samba

1) NULL pointer dereference

EUVDB-ID: #VU57324

Risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-3671

CWE-ID: CWE-476 - NULL Pointer Dereference

Exploit availability: No

Description

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

The vulnerability exists due to a NULL pointer dereference error in the way samba kerberos server handles missing sname attribute in TGS-REQ (Ticket Granting Server - Request). A remote authenticated user can send a specially crafted request to the samba server and perform a denial of service (DoS) attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Samba: 4.13.0 - 4.14.7

CPE2.3

• cpe:2.3:a:samba:samba:4.13.0:*:*:*:*:*:*:*
• cpe:2.3:a:samba:samba:4.13.1:*:*:*:*:*:*:*
• cpe:2.3:a:samba:samba:4.13.2:*:*:*:*:*:*:*
• cpe:2.3:a:samba:samba:4.13.3:*:*:*:*:*:*:*
• cpe:2.3:a:samba:samba:4.13.4:*:*:*:*:*:*:*
• cpe:2.3:a:samba:samba:4.13.5:*:*:*:*:*:*:*
• cpe:2.3:a:samba:samba:4.13.6:*:*:*:*:*:*:*
• cpe:2.3:a:samba:samba:4.13.7:*:*:*:*:*:*:*
• cpe:2.3:a:samba:samba:4.13.8:*:*:*:*:*:*:*
• cpe:2.3:a:samba:samba:4.13.9:*:*:*:*:*:*:*

External links

https://bugzilla.samba.org/show_bug.cgi?id=14770
https://bugzilla.redhat.com/show_bug.cgi?id=2013080
https://github.com/heimdal/heimdal/commit/04171147948d0a3636bc6374181926f0fb2ec83a

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the local network (LAN).

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.