CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.0	$0-$5k	0.00

A vulnerability, which was classified as problematic, has been found in Ubuntu Linux (Operating System) (version now known). Affected by this issue is some unknown processing of the component base-files package. The manipulation with an unknown input leads to a link following vulnerability. Using CWE to declare the problem leads to CWE-59. The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource. Impacted is confidentiality, integrity, and availability. CVE summarizes:

The MOTD update script in the base-files package in Ubuntu 18.04 LTS before 10.1ubuntu2.2, and Ubuntu 18.10 before 10.1ubuntu6 incorrectly handled temporary files. A local attacker could use this issue to cause a denial of service, or possibly escalate privileges if kernel symlink restrictions were disabled.

The bug was discovered 08/21/2018. The weakness was disclosed 08/21/2018 by Sander Bos (Website). The advisory is available at usn.ubuntu.com. This vulnerability is handled as CVE-2018-6557 since 02/01/2018. Local access is required to approach this attack. Required for exploitation is a simple authentication. The technical details are unknown and an exploit is not available.

The vulnerability scanner Nessus provides a plugin with the ID 112058 (Ubuntu 18.04 LTS : base-files vulnerability (USN-3748-1)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Ubuntu Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 197236 (Ubuntu Security Notification for Base-files Vulnerability (USN-3748-1)).

Upgrading eliminates this vulnerability. A possible mitigation has been published 2 hours after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (112058).

Productinfo

Type

• Operating System

Vendor

• Ubuntu

Name

• Linux

License

• open-source

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

CVSSv4info

VulDB CVSS-B Score: 🔍
VulDB CVSS-BT Score: 🔍
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.1
VulDB Meta Temp Score: 6.0

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.0
NVD Vector: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
unlock	unlock	unlock	unlock	unlock	unlock
unlock	unlock	unlock	unlock	unlock	unlock
unlock	unlock	unlock	unlock	unlock	unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Link following
CWE: CWE-59
CAPEC: 🔍
ATT&CK: 🔍

Local: Yes
Remote: No

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	unlock	unlock	unlock	unlock
Today	unlock	unlock	unlock	unlock

Nessus ID: 112058
Nessus Name: Ubuntu 18.04 LTS : base-files vulnerability (USN-3748-1)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

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

Timelineinfo

02/01/2018 🔍
08/21/2018 +200 days 🔍
08/21/2018 +0 days 🔍
08/21/2018 +0 days 🔍
08/21/2018 +0 days 🔍
08/21/2018 +0 days 🔍
08/22/2018 +1 days 🔍
08/22/2018 +0 days 🔍
05/04/2023 +1716 days 🔍

Sourcesinfo

Vendor: ubuntu.com

Advisory: USN-3748-1
Researcher: Sander Bos
Status: Not defined

CVE: CVE-2018-6557 (🔍)
SecurityTracker: 1041530
SecurityFocus: 105148 - Debian Linux MOTD Update Script CVE-2018-6557 Insecure Temporary File Handling Vulnerability

Entryinfo

Created: 08/22/2018 06:55
Updated: 05/04/2023 08:35
Changes: 08/22/2018 06:55 (70), 03/17/2020 13:19 (5), 05/04/2023 08:35 (5)
Complete: 🔍

Discussion

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