Ubuntu update for samba



Published: 2021-05-03
Risk Medium
Patch available YES
Number of vulnerabilities 4
CVE-ID CVE-2020-14318
CVE-2020-14323
CVE-2020-14383
CVE-2021-20254
CWE-ID CWE-264
CWE-476
CWE-119
CWE-125
Exploitation vector Network
Public exploit N/A
Vulnerable software
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Ubuntu
Operating systems & Components / Operating system

samba (Ubuntu package)
Operating systems & Components / Operating system package or component

Vendor Canonical Ltd.

Security Bulletin

This security bulletin contains information about 4 vulnerabilities.

1) Permissions, Privileges, and Access Controls

EUVDB-ID: #VU47990

Risk: Low

CVSSv3.1: 3.8 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-14318

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Exploit availability: No

Description

The vulnerability allows a remote user to gain access to sensitive information.

The vulnerability exists due to the way "ChangeNotify" concept for SMB1/2/3 protocols was implemented in Samba. A missing permissions check on a directory handle requesting ChangeNotify means that a client with a directory handle open only for FILE_READ_ATTRIBUTES (minimal access rights) could be used to obtain change notify replies from the server. These replies contain information that should not be available to directory handles open for FILE_READ_ATTRIBUTE only. A local unprivileged user can abuse this lack of permissions check to obtain information about file changes.

Mitigation

Update the affected package samba to the latest version.

Vulnerable software versions

Ubuntu: 14.04

samba (Ubuntu package): before 2:4.3.11+dfsg0ubuntu0.14.04.20+esm11

External links

http://ubuntu.com/security/notices/USN-4931-1


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

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

2) NULL pointer dereference

EUVDB-ID: #VU47991

Risk: Medium

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

CVE-ID: CVE-2020-14323

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 when processing requests in winbind in Samba. A remote user can send specially crafted request to winbind daemon, trigger a NULL pointer dereference error and crash it.

Mitigation

Update the affected package samba to the latest version.

Vulnerable software versions

Ubuntu: 14.04

samba (Ubuntu package): before 2:4.3.11+dfsg0ubuntu0.14.04.20+esm11

External links

http://ubuntu.com/security/notices/USN-4931-1


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

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

3) Memory corruption

EUVDB-ID: #VU47993

Risk: Low

CVSSv3.1: 3.8 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-14383

CWE-ID: CWE-119 - Memory corruption

Exploit availability: No

Description

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

The vulnerability exists due to a boundary error when processing DNS records. A remote user

 with ability to create MX or NS records with absent properties can trigger the RPC service to dereference uninitialized memory and will result in denial of service attack against the RPC service.

Mitigation

Update the affected package samba to the latest version.

Vulnerable software versions

Ubuntu: 14.04

samba (Ubuntu package): before 2:4.3.11+dfsg0ubuntu0.14.04.20+esm11

External links

http://ubuntu.com/security/notices/USN-4931-1


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

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

4) Out-of-bounds read

EUVDB-ID: #VU52748

Risk: Medium

CVSSv3.1: 4 [CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-20254

CWE-ID: CWE-125 - Out-of-bounds read

Exploit availability: No

Description

The vulnerability allows a remote user to gain access to potentially sensitive information.

The vulnerability exists due to a boundary condition when mapping Windows group identities (SIDs) into unix group identities (gids), which resulted into negative idmap cache entries created in the Samba server process token. An attacker who can manage to trigger the vulnerability can crash the Samba server or potentially perform unauthorized actions on the system.

Mitigation

Update the affected package samba to the latest version.

Vulnerable software versions

Ubuntu: 14.04

samba (Ubuntu package): before 2:4.3.11+dfsg0ubuntu0.14.04.20+esm11

External links

http://ubuntu.com/security/notices/USN-4931-1


Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

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



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