CyberSecBulletin
CVE-2024-0840NVD status: Deferred

UCM Series: Improper Neutralization of Parameter/Argument Delimiters

Published Updated By the CyberSecBulletin desk

CVE-2024-0840 is a high-severity improper neutralization of parameter/argument delimiters vulnerability in UCM Series from Grandstream, 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 version <1.0.20.52 as the first without the flaw, so updating UCM Series to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.88% chance of exploitation within 30 days, higher than 60% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update UCM Series to <1.0.20.52 or a later version.
  2. Update ucm6202_firmware to 1.0.20.52 or a later version.
  3. Update ucm6204_firmware to 1.0.20.52 or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
GrandstreamUCM Seriesbefore <1.0.20.52<1.0.20.52
Grandstreamucm6202_firmwarebefore 1.0.20.521.0.20.52
Grandstreamucm6204_firmwarebefore 1.0.20.521.0.20.52
Grandstreamucm6208_firmwarebefore 1.0.20.521.0.20.52
Grandstreamucm6510_firmwarebefore 1.0.20.521.0.20.52

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 CNA (vulncheck.com).

Official description

The Grandstream UCM Series IP PBX before firmware version 1.0.20.52 is affected by a parameter injection vulnerability in the HTTP interface. A remote and authenticated attacker can execute arbitrary code by sending a crafted HTTP request. Authentication may be possible using a default user and password. Affected models are the UCM6202, UCM6204, UCM6208, and UCM6510.

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

The underlying weakness: Improper Neutralization of Parameter/Argument Delimiters

The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as parameter or argument delimiters when they are sent to a downstream component.

How developers prevent this class of flaw

  • Developers should anticipate that parameter/argument delimiters will be injected/removed/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appropriate input is processed by the system.
  • While it is risky to use dynamically-generated query strings, code, or commands that mix control and data together, sometimes it may be unavoidable. Properly quote arguments and escape any special characters within those arguments. The most conservative approach is to escape or filter all characters that do not pass an extremely strict allowlist (such as everything that is not alphanumeric or white space). If some special characters are still needed, such as white space, wrap each argument in quotes after the escaping/filtering step. Be careful of argument injection (CWE-88).
  • Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.

More Improper Neutralization of Parameter/Argument Delimiters vulnerabilities (CWE-141)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Improper Neutralization of Parameter/Argument Delimiters vulnerabilities

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