Amazon Linux AMI update for samba

Published: 2020-09-01

Risk	Medium
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2019-10197 CVE-2019-10218
CWE-ID	CWE-264 CWE-22
Exploitation vector	Network
Public exploit	N/A
Vulnerable software Subscribe	Amazon Linux AMI Operating systems & Components / Operating system
Vendor	Amazon Web Services

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Permissions, Privileges, and Access Controls

EUVDB-ID: #VU20809

Risk: Medium

CVSSv3.1: 5.3 [CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-10197

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

Exploit availability: No

Description

The vulnerability allows a remote attacker to escalate privileges on the system.

The vulnerability exists due to an error related to caching of responses when the 'wide links' option is explicitly set to 'yes' and either 'unix extensions = no' or 'allow insecure wide links = yes' is set in addition. A remote attacker can that does not have access to a share can send a series of request to an SMB share and gain access to the global root directory on the system.

Successful exploitation of the vulnerability may allow an attacker to read or modify arbitrary files on the system. Note, that unix permissions enforced by kernel will still apply.

Mitigation

Update the affected packages:

i686:
    libwbclient-devel-4.10.4-11.51.amzn1.i686
    samba-client-libs-4.10.4-11.51.amzn1.i686
    samba-krb5-printing-4.10.4-11.51.amzn1.i686
    libsmbclient-4.10.4-11.51.amzn1.i686
    samba-winbind-modules-4.10.4-11.51.amzn1.i686
    samba-test-libs-4.10.4-11.51.amzn1.i686
    libwbclient-4.10.4-11.51.amzn1.i686
    samba-common-tools-4.10.4-11.51.amzn1.i686
    ctdb-4.10.4-11.51.amzn1.i686
    samba-client-4.10.4-11.51.amzn1.i686
    samba-4.10.4-11.51.amzn1.i686
    samba-debuginfo-4.10.4-11.51.amzn1.i686
    libsmbclient-devel-4.10.4-11.51.amzn1.i686
    samba-winbind-krb5-locator-4.10.4-11.51.amzn1.i686
    samba-libs-4.10.4-11.51.amzn1.i686
    samba-python-4.10.4-11.51.amzn1.i686
    samba-winbind-4.10.4-11.51.amzn1.i686
    samba-test-4.10.4-11.51.amzn1.i686
    samba-common-libs-4.10.4-11.51.amzn1.i686
    samba-python-test-4.10.4-11.51.amzn1.i686
    samba-devel-4.10.4-11.51.amzn1.i686
    samba-winbind-clients-4.10.4-11.51.amzn1.i686
    ctdb-tests-4.10.4-11.51.amzn1.i686

noarch:
    samba-common-4.10.4-11.51.amzn1.noarch
    samba-pidl-4.10.4-11.51.amzn1.noarch

src:
    samba-4.10.4-11.51.amzn1.src

x86_64:
    samba-devel-4.10.4-11.51.amzn1.x86_64
    ctdb-4.10.4-11.51.amzn1.x86_64
    samba-test-libs-4.10.4-11.51.amzn1.x86_64
    samba-4.10.4-11.51.amzn1.x86_64
    samba-krb5-printing-4.10.4-11.51.amzn1.x86_64
    ctdb-tests-4.10.4-11.51.amzn1.x86_64
    samba-test-4.10.4-11.51.amzn1.x86_64
    samba-common-tools-4.10.4-11.51.amzn1.x86_64
    samba-libs-4.10.4-11.51.amzn1.x86_64
    libsmbclient-devel-4.10.4-11.51.amzn1.x86_64
    samba-winbind-clients-4.10.4-11.51.amzn1.x86_64
    libwbclient-4.10.4-11.51.amzn1.x86_64
    samba-python-4.10.4-11.51.amzn1.x86_64
    samba-debuginfo-4.10.4-11.51.amzn1.x86_64
    samba-winbind-krb5-locator-4.10.4-11.51.amzn1.x86_64
    samba-client-libs-4.10.4-11.51.amzn1.x86_64
    samba-client-4.10.4-11.51.amzn1.x86_64
    libsmbclient-4.10.4-11.51.amzn1.x86_64
    samba-python-test-4.10.4-11.51.amzn1.x86_64
    libwbclient-devel-4.10.4-11.51.amzn1.x86_64
    samba-winbind-modules-4.10.4-11.51.amzn1.x86_64
    samba-common-libs-4.10.4-11.51.amzn1.x86_64
    samba-winbind-4.10.4-11.51.amzn1.x86_64

Vulnerable software versions

Amazon Linux AMI: All versions

External links

http://alas.aws.amazon.com/ALAS-2020-1424.html

Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

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

2) Path traversal

EUVDB-ID: #VU22329

Risk: Medium

CVSSv3.1: 4.6 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-10218

CWE-ID: CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform directory traversal attacks.

The vulnerability exists due to input validation error when processing directory traversal sequences in filenames within Samba client code (libsmbclient). A malicious SMB server can return a filename to the client containing directory traversal characters and force the client to read or write data to local files.

Successful exploitation of the vulnerability may allow an attacker to overwrite arbitrary files on the client.

Mitigation

Update the affected packages:

i686:
    libwbclient-devel-4.10.4-11.51.amzn1.i686
    samba-client-libs-4.10.4-11.51.amzn1.i686
    samba-krb5-printing-4.10.4-11.51.amzn1.i686
    libsmbclient-4.10.4-11.51.amzn1.i686
    samba-winbind-modules-4.10.4-11.51.amzn1.i686
    samba-test-libs-4.10.4-11.51.amzn1.i686
    libwbclient-4.10.4-11.51.amzn1.i686
    samba-common-tools-4.10.4-11.51.amzn1.i686
    ctdb-4.10.4-11.51.amzn1.i686
    samba-client-4.10.4-11.51.amzn1.i686
    samba-4.10.4-11.51.amzn1.i686
    samba-debuginfo-4.10.4-11.51.amzn1.i686
    libsmbclient-devel-4.10.4-11.51.amzn1.i686
    samba-winbind-krb5-locator-4.10.4-11.51.amzn1.i686
    samba-libs-4.10.4-11.51.amzn1.i686
    samba-python-4.10.4-11.51.amzn1.i686
    samba-winbind-4.10.4-11.51.amzn1.i686
    samba-test-4.10.4-11.51.amzn1.i686
    samba-common-libs-4.10.4-11.51.amzn1.i686
    samba-python-test-4.10.4-11.51.amzn1.i686
    samba-devel-4.10.4-11.51.amzn1.i686
    samba-winbind-clients-4.10.4-11.51.amzn1.i686
    ctdb-tests-4.10.4-11.51.amzn1.i686

noarch:
    samba-common-4.10.4-11.51.amzn1.noarch
    samba-pidl-4.10.4-11.51.amzn1.noarch

src:
    samba-4.10.4-11.51.amzn1.src

x86_64:
    samba-devel-4.10.4-11.51.amzn1.x86_64
    ctdb-4.10.4-11.51.amzn1.x86_64
    samba-test-libs-4.10.4-11.51.amzn1.x86_64
    samba-4.10.4-11.51.amzn1.x86_64
    samba-krb5-printing-4.10.4-11.51.amzn1.x86_64
    ctdb-tests-4.10.4-11.51.amzn1.x86_64
    samba-test-4.10.4-11.51.amzn1.x86_64
    samba-common-tools-4.10.4-11.51.amzn1.x86_64
    samba-libs-4.10.4-11.51.amzn1.x86_64
    libsmbclient-devel-4.10.4-11.51.amzn1.x86_64
    samba-winbind-clients-4.10.4-11.51.amzn1.x86_64
    libwbclient-4.10.4-11.51.amzn1.x86_64
    samba-python-4.10.4-11.51.amzn1.x86_64
    samba-debuginfo-4.10.4-11.51.amzn1.x86_64
    samba-winbind-krb5-locator-4.10.4-11.51.amzn1.x86_64
    samba-client-libs-4.10.4-11.51.amzn1.x86_64
    samba-client-4.10.4-11.51.amzn1.x86_64
    libsmbclient-4.10.4-11.51.amzn1.x86_64
    samba-python-test-4.10.4-11.51.amzn1.x86_64
    libwbclient-devel-4.10.4-11.51.amzn1.x86_64
    samba-winbind-modules-4.10.4-11.51.amzn1.x86_64
    samba-common-libs-4.10.4-11.51.amzn1.x86_64
    samba-winbind-4.10.4-11.51.amzn1.x86_64

Vulnerable software versions

Amazon Linux AMI: All versions

External links

http://alas.aws.amazon.com/ALAS-2020-1424.html

Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

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