zsh up to 5.4.2 subst.c ${(PA)...} null pointer dereference

CVSS Meta Temp Score
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CTI Interest Score
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7.3$0-$5k0.00

Summaryinfo

A vulnerability was found in zsh up to 5.4.2 and classified as problematic. The affected element is an unknown function of the file subst.c. The manipulation of the argument ${(PA)...} results in null pointer dereference. This vulnerability is reported as CVE-2018-7548. The attack can be launched remotely. Moreover, an exploit is present. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in zsh up to 5.4.2. Affected is an unknown code of the file subst.c. The manipulation of the argument ${(PA)...} with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. CVE summarizes:

In subst.c in zsh through 5.4.2, there is a NULL pointer dereference when using ${(PA)...} on an empty array result.

The bug was discovered 02/27/2018. The weakness was disclosed 02/27/2018 (Website). The advisory is available at sourceforge.net. This vulnerability is traded as CVE-2018-7548 since 02/27/2018. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details and a public exploit are known.

It is declared as proof-of-concept. The vulnerability scanner Nessus provides a plugin with the ID 109139 (Amazon Linux 2 : zsh (ALAS-2018-986)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Amazon Linux Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 197077 (Ubuntu Security Notification for Zsh Vulnerabilities (USN-3593-1)).

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

The vulnerability is also documented in the vulnerability database at Tenable (109139). The entries VDB-113892, VDB-113902, VDB-113903 and VDB-113923 are pretty similar. If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.6
VulDB Meta Temp Score: 7.3

VulDB Base Score: 5.3
VulDB Temp Score: 4.8
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 9.8
NVD Vector: 🔍

CVSSv2info

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

NVD Base Score: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 109139
Nessus Name: Amazon Linux 2 : zsh (ALAS-2018-986)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 65476
OpenVAS Name: Fedora Update for zsh FEDORA-2018-9cdf18a850
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

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

Patch: sourceforge.net

Timelineinfo

02/27/2018 🔍
02/27/2018 +0 days 🔍
02/27/2018 +0 days 🔍
02/27/2018 +0 days 🔍
02/28/2018 +1 days 🔍
04/05/2018 +36 days 🔍
04/18/2018 +13 days 🔍
02/16/2023 +1765 days 🔍

Sourcesinfo

Advisory: 110b13e1
Status: Not defined

CVE: CVE-2018-7548 (🔍)
GCVE (CVE): GCVE-0-2018-7548
GCVE (VulDB): GCVE-100-113922
scip Labs: https://www.scip.ch/en/?labs.20161013
See also: 🔍

Entryinfo

Created: 02/28/2018 09:18
Updated: 02/16/2023 08:43
Changes: 02/28/2018 09:18 (73), 01/09/2020 11:18 (3), 02/16/2023 08:38 (5), 02/16/2023 08:43 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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