Multiple vulnerabilities in Digium Asterisk and Certified Asterisk

Published: 2019-11-22

Risk	High
Patch available	YES
Number of vulnerabilities	3
CVE-ID	CVE-2019-18790 CVE-2019-18976 CVE-2019-18610
CWE-ID	CWE-284 CWE-20 CWE-78
Exploitation vector	Network
Public exploit	N/A
Vulnerable software Subscribe	Asterisk Open Source Server applications / Conferencing, Collaboration and VoIP solutions Certified Asterisk Server applications / Conferencing, Collaboration and VoIP solutions
Vendor	Digium (Linux Support Services)

Security Bulletin

This security bulletin contains information about 3 vulnerabilities.

1) Improper access control

EUVDB-ID: #VU22934

Risk: Medium

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

CVE-ID: CVE-2019-18790

CWE-ID: CWE-284 - Improper Access Control

Exploit availability: No

Description

The vulnerability allows a remote attacker to gain unauthorized access to otherwise restricted functionality.

The vulnerability exists due to improper access restrictions. A remote attacker can send a specially crafted SIP request, change a SIP peer’s IP address and hijack the calls.

Note: This vulnerability is only exploitable when the “nat” option is set to the default, or “auto_force_rport”.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Asterisk Open Source: 13.0.0 - 17.0.0

Certified Asterisk: 13.21 - 13.21-cert4

CPE2.3

External links

http://seclists.org/fulldisclosure/2019/Nov/18
http://www.asterisk.org/downloads/security-advisories
http://issues.asterisk.org/jira/browse/ASTERISK-28589

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.

2) Input validation error

EUVDB-ID: #VU22936

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-18976

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

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

The vulnerability exists due to insufficient validation of user-supplied input in the "res_pjsip_t38.c" module. A remote attacker can cause a denial of service condition when Asterisk receives a re-invite initiating T.38 faxing and has a port of 0 and no c line in the SDP.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Asterisk Open Source: 13.0.0 - 13.29.1

Certified Asterisk: 13.21 - 13.21-cert4

CPE2.3

External links

http://seclists.org/fulldisclosure/2019/Nov/20
http://issues.asterisk.org/jira/browse/ASTERISK-28612

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.

3) OS Command Injection

EUVDB-ID: #VU22935

Risk: High

CVSSv3.1: 7.7 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-18610

CWE-ID: CWE-78 - Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

Exploit availability: No

Description

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

The vulnerability exists due to improper input validation in the "manager.c" module. A remote authenticated Asterisk Manager Interface (AMI) user without “system” authorization can use a specially crafted “Originate” AMI request to execute arbitrary system commands.

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

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Asterisk Open Source: 13.0.0 - 17.0.0

Certified Asterisk: 13.21 - 13.21-cert4

CPE2.3

External links

http://seclists.org/fulldisclosure/2019/Nov/19
http://issues.asterisk.org/jira/browse/ASTERISK-28580
http://www.asterisk.org/downloads/security-advisories

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.