Multiple vulnerabilities in FreeBSD

Published: 2020-09-03 | Updated: 2022-11-30

Risk	Medium
Patch available	YES
Number of vulnerabilities	5
CVE-ID	CVE-2020-7463 CVE-2020-7461 CVE-2020-7462
CWE-ID	CWE-617 CWE-824 CWE-416 CWE-122
Exploitation vector	Local network
Public exploit	Public exploit code for vulnerability #4 is available.
Vulnerable software	FreeBSD Operating systems & Components / Operating system
Vendor	FreeBSD Foundation

Security Bulletin

This security bulletin contains information about 5 vulnerabilities.

1) Reachable Assertion

EUVDB-ID: #VU46229

Risk: Low

CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: N/A

CWE-ID: CWE-617 - Reachable Assertion

Exploit availability: No

Description

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

The vulnerability exists due to improper handling of exec(3) calls in Linux ABI layer (Linuxulator) when calling processes with multiple threads. A local user can run a specially crafted program to trigger an assertion failure and cause kernel panic.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

FreeBSD: 11.0 - 12.1

CPE2.3

External links

https://www.freebsd.org/security/advisories/FreeBSD-EN-20:17.linuxthread.asc

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

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

2) Access of Uninitialized Pointer

EUVDB-ID: #VU46228

Risk: Low

CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: N/A

CWE-ID: CWE-824 - Access of Uninitialized Pointer

Exploit availability: No

Description

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

The vulnerability exists due to an error in internal interface used by getfsstat(2) compatibility system. A local unprivileged user can run a program that calls getfsstat(2) with an invalid argument, which causes getfsstat(2) to free an uninitialized pointer and results in kernel panic.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

FreeBSD: 11.0 - 11.4

CPE2.3

External links

https://www.freebsd.org/security/advisories/FreeBSD-EN-20:18.getfsstat.asc

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

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

3) Use-after-free

EUVDB-ID: #VU46227

Risk: Low

CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2020-7463

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

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

The vulnerability exists due to a use-after-free error when processing SCTP messages. A local user can send large user messages from multiple threads on the same socket., trigger a use-after-free error and crash the system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

FreeBSD: 11.0 - 12.1

CPE2.3

External links

https://www.freebsd.org/security/advisories/FreeBSD-SA-20:25.sctp.asc

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

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

4) Heap-based buffer overflow

EUVDB-ID: #VU46226

Risk: Medium

CVSSv4.0: 7.4 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Green]

CVE-ID: CVE-2020-7461

CWE-ID: CWE-122 - Heap-based Buffer Overflow

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error when parsing option 119 data in DHCP packets in dhclient(8). A remote attacker on the local network can send specially crafted data to the DHCP client, trigger heap-based buffer overflow and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

FreeBSD: 11.0 - 12.1

CPE2.3

External links

https://www.freebsd.org/security/advisories/FreeBSD-SA-20:26.dhclient.asc

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. However, proof of concept for this vulnerability is available.

5) Use-after-free

EUVDB-ID: #VU46225

Risk: Low

CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2020-7462

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

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

The vulnerability exists due to a use-after-free error when processing IPv6 packets. A local user can send IPv6 Hop-by-Hop options over the loopback interface and trigger kernel panic.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

FreeBSD: 11.0 - 11.4

CPE2.3

External links

https://www.freebsd.org/security/advisories/FreeBSD-SA-20:24.ipv6.asc

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

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