CyberSecBulletin
CVE-2024-42365NVD status: Modified

asterisk: Privilege Defined With Unsafe Actions

Published Updated By the CyberSecBulletin desk

CVE-2024-42365 is a high-severity privilege defined with unsafe actions vulnerability in asterisk, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists versions 18.24.2, 20.9.2, 21.4.2 as the first without the flaw, so updating asterisk to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 4.7% chance of exploitation within 30 days, which is in the top 8.05% of all scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update asterisk to 18.24.2 or 20.9.2 or 21.4.2, whichever matches your release line, or a later version.
  2. Update certified_asterisk to 18.9-cert11 or 20.7-cert2, whichever matches your release line, or a later version.
  3. Read the advisory on github.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
Asteriskasterisk< 18.24.2; >= 19.0.0, < 20.9.2; >= 21.0.0, < 21.4.2; < 18.9-cert11; >= 19.0, < 20.7-cert2; before 18.24.2; 19.0.0 up to, but not including, 20.9.2; 21.0.0 up to, but not including, 21.4.218.24.2, 20.9.2, 21.4.2
Asteriskcertified_asteriskbefore 18.9-cert11; 19.0 up to, but not including, 20.7-cert218.9-cert11, 20.7-cert2

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.4HighCNA (github.com)
CVSS 3.18.8HighNVD

Official description

Asterisk is an open source private branch exchange (PBX) and telephony toolkit. Prior to asterisk versions 18.24.2, 20.9.2, and 21.4.2 and certified-asterisk versions 18.9-cert11 and 20.7-cert2, an AMI user with `write=originate` may change all configuration files in the `/etc/asterisk/` directory. This occurs because they are able to curl remote files and write them to disk, but are also able to append to existing files using the `FILE` function inside the `SET` application. This issue may result in privilege escalation, remote code execution and/or blind server-side request forgery with arbitrary protocol. Asterisk versions 18.24.2, 20.9.2, and 21.4.2 and certified-asterisk versions 18.9-cert11 and 20.7-cert2 contain a fix for this issue.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Privilege Defined With Unsafe Actions

A particular privilege, role, capability, or right can be used to perform unsafe actions that were not intended, even when it is assigned to the correct entity.

How developers prevent this class of flaw

  • Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.
  • Run your code using the lowest privileges that are required to accomplish the necessary tasks. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.

More Privilege Defined With Unsafe Actions vulnerabilities (CWE-267)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in asterisk

All asterisk vulnerabilities

Recent Privilege Defined With Unsafe Actions vulnerabilities

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