CyberSecBulletin
CVE-2023-53929NVD status: Analyzed

phpMyFAQ: Improper Neutralization of Formula Elements in a CSV File

Published Updated By the CyberSecBulletin desk

CVE-2023-53929 is a high-severity improper neutralization of formula elements in a CSV file vulnerability in phpMyFAQ, with a CVSS 3.1 base score of 8.0 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, but only if a user takes part, for example by opening a link or file. Affected phpMyFAQ versions: 3.1.12. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.54% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of phpMyFAQ you run against the affected versions below, and install the vendor's latest release.
  2. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
PhpmyfaqphpMyFAQ3.1.12Not stated

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
RequiredA user must take an action such as opening a file or link.
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:R/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 4.06.2MediumCNA (vulncheck.com)
CVSS 3.18.8HighCNA (vulncheck.com)
CVSS 3.18.0HighNVD

Official description

phpMyFAQ 3.1.12 contains a CSV injection vulnerability that allows authenticated users to inject malicious formulas into their profile names. Attackers can modify their user profile name with a payload like 'calc|a!z|' to trigger code execution when an administrator exports user data as a CSV file.

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

The underlying weakness: Improper Neutralization of Formula Elements in a CSV File

The product saves user-provided information into a Comma-Separated Value (CSV) file, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as a command when the file is opened by a spreadsheet product.

How developers prevent this class of flaw

  • When generating CSV output, ensure that formula-sensitive metacharacters are effectively escaped or removed from all data before storage in the resultant CSV. Risky characters include '=' (equal), '+' (plus), '-' (minus), and '@' (at).
  • If a field starts with a formula character, prepend it with a ' (single apostrophe), which prevents Excel from executing the formula.
  • Certain implementations of spreadsheet software might disallow formulas from executing if the file is untrusted, or if the file is not authored by the current user.

More Improper Neutralization of Formula Elements in a CSV File vulnerabilities (CWE-1236)

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

Third-party and government advisories

Technical write-ups (may include proof of concept)

Other references

Other vulnerabilities in phpMyFAQ

All phpMyFAQ vulnerabilities

Recent Improper Neutralization of Formula Elements in a CSV File vulnerabilities

Spotted an error? Tell us.