FreeBSD up to 11.0 telnetd login(1) improper authentication

CVSS Meta Temp Score
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CTI Interest Score
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7.2$0-$5k0.00

Summaryinfo

A vulnerability was found in FreeBSD 9.3/10.1/10.2/10.3/11.0 and classified as critical. Affected is the function login(1) of the component telnetd. The manipulation results in improper authentication. This vulnerability is reported as CVE-2016-1888. The attack can be launched remotely. No exploit exists. It is advisable to implement a patch to correct this issue.

Detailsinfo

A vulnerability, which was classified as critical, was found in FreeBSD 9.3/10.1/10.2/10.3/11.0 (Operating System). Affected is the function login(1) of the component telnetd. The manipulation with an unknown input leads to a improper authentication vulnerability. CWE is classifying the issue as CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

The telnetd service in FreeBSD 9.3, 10.1, 10.2, 10.3, and 11.0 allows remote attackers to inject arguments to login and bypass authentication via vectors involving a "sequence of memory allocation failures."

The bug was discovered 12/06/2016. The weakness was disclosed 12/06/2016 by Brooks Davis as FreeBSD-SA-16:36.telnetd as confirmed security advisory (Website). The advisory is shared for download at security.FreeBSD.org. The public release has been coordinated in cooperation with the vendor. This vulnerability is traded as CVE-2016-1888 since 01/13/2016. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The advisory points out:

The FreeBSD telnet daemon, telnetd(8), implements the server side of the TELNET virtual terminal protocol. It has been disabled by default in FreeBSD since August 2001, and due to the lack of cryptographic security in the TELNET protocol, it is strongly recommended that the SSH protocol be used instead. The FreeBSD telnet daemon can be enabled via the /etc/inetd.conf configuration file and the inetd(8) daemon. After a user is connected, telnetd executes the login(1) program or a similar program specified by the -p <loginprog> argument. In order to do so, it constructs an array of command line arguments which are passed to execv(3).

The vulnerability scanner Nessus provides a plugin with the ID 95587 (FreeBSD : FreeBSD -- Possible login(1) argument injection in telnetd(8) (e00304d2-bbed-11e6-b1cf-14dae9d210b8)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family FreeBSD Local Security Checks and running in the context l.

Applying a patch is able to eliminate this problem. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (95587) and SecurityTracker (ID 1037399†). The entry VDB-93973 is pretty similar. Once again VulDB remains the best source for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 7.3

VulDB Base Score: 7.5
VulDB Temp Score: 7.2
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Improper authentication
CWE: CWE-287
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 95587
Nessus Name: FreeBSD : FreeBSD -- Possible login(1) argument injection in telnetd(8) (e00304d2-bbed-11e6-b1cf-14dae9d210b8)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Timelineinfo

01/13/2016 🔍
12/06/2016 +328 days 🔍
12/06/2016 +0 days 🔍
12/06/2016 +0 days 🔍
12/06/2016 +0 days 🔍
12/07/2016 +1 days 🔍
12/07/2016 +0 days 🔍
02/15/2017 +70 days 🔍
06/19/2019 +854 days 🔍

Sourcesinfo

Product: freebsd.org

Advisory: FreeBSD-SA-16:36.telnetd
Researcher: Brooks Davis
Status: Confirmed
Coordinated: 🔍

CVE: CVE-2016-1888 (🔍)
GCVE (CVE): GCVE-0-2016-1888
GCVE (VulDB): GCVE-100-93972
SecurityTracker: 1037399

See also: 🔍

Entryinfo

Created: 12/07/2016 10:39
Updated: 06/19/2019 17:35
Changes: 12/07/2016 10:39 (67), 06/19/2019 17:35 (10)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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