Appointment Hour Booking – Booking Calendar: Improper Neutralization of Formula Elements in a CSV File
CVE-2022-4034 is a high-severity improper neutralization of formula elements in a CSV file vulnerability in Appointment Hour Booking – Booking Calendar from CodePeople, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected Appointment Hour Booking – Booking Calendar versions: 1.3.72 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.68% chance of exploitation within 30 days, higher than 53% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Appointment Hour Booking – Booking Calendar you run against the affected versions below, and install the vendor's latest release.
- 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
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Codepeople | Appointment Hour Booking – Booking Calendar | 1.3.72 and earlier | Not stated |
| Dwbooster | Appointment Hour Booking | 1.3.72 and earlier | Not 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
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- 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:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 5.8 | Medium | CNA (wordfence.com) |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
The Appointment Hour Booking Plugin for WordPress is vulnerable to CSV Injection in versions up to, and including, 1.3.72. This makes it possible for unauthenticated attackers to embed untrusted input into content during booking creation that may be exported as a CSV file when a site's administrator exports booking details. This can result in code execution when these files are downloaded and opened on a local system with a vulnerable configuration.
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
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Third-party and government advisories
- wordfence.com/vulnerability-advisories-continued/#CVE-2022-4034Third Party Advisory
Other references
Other vulnerabilities in Appointment Hour Booking – Booking Calendar
- 7.2 High severity
Recent Improper Neutralization of Formula Elements in a CSV File vulnerabilities
- 8.0 High severity
- 7.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 8.8 High severity
- 8.0 High severity
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