# WinRAR zero-day used against traders, then state hackers (CVE-2023-38831) · pwn.watch

> WinRAR before 6.23 would run hidden code when a user opened what looked like a harmless file inside a ZIP. Group-IB found it exploited since April 2023 to target traders. After the fix, Google TAG saw Russian and Chinese government-backed groups pile on.

Page: https://pwn.watch/i/winrar-zero-day-cve-2023-38831 · generated 2026-10-22T19:29:07.289Z

## Status
- Severity: high · status: closed · patch: patched
- Product: RARLAB WinRAR
- Started: 2023-08-02 · closed: 2023-10-18
- CVEs: CVE-2023-38831
- Affected: Before 6.23 (NVD)
- Fixed in: 6.23

## Follow this incident
- RSS (one item per update): https://pwn.watch/i/winrar-zero-day-cve-2023-38831/feed.xml
- JSON Feed: https://pwn.watch/i/winrar-zero-day-cve-2023-38831/feed.json
- Full data (timeline, sources, posts, agentBrief): https://pwn.watch/i/winrar-zero-day-cve-2023-38831.json
- This file: https://pwn.watch/i/winrar-zero-day-cve-2023-38831/llms.txt

## Updates (newest first)
- 2023-10-18: Google TAG: government-backed actors exploiting the WinRAR bug (https://blog.google/threat-analysis-group/government-backed-actors-exploiting-winrar-vulnerability/)
- 2023-08-24: CISA adds CVE-2023-38831 to the KEV catalog
- 2023-08-23: Group-IB: zero-day exploited since April 2023 against traders (https://www.group-ib.com/blog/cve-2023-38831-winrar-zero-day/)
- 2023-08-02: WinRAR 6.23 released with the fix (https://www.rarlab.com/rarnew.htm)

## Fix brief
# Security brief: WinRAR zero-day used against traders, then state hackers (CVE-2023-38831)

Source: https://pwn.watch/i/winrar-zero-day-cve-2023-38831 · status: closed (closed Oct 18, 2023) · severity: high · updated Oct 18, 2023

## Patch status
**PATCHED: fixed releases exist. Upgrade to a fixed version.**

## What it is
WinRAR before 6.23 would run hidden code when a user opened what looked like a harmless file inside a ZIP. Group-IB found it exploited since April 2023 to target traders. After the fix, Google TAG saw Russian and Chinese government-backed groups pile on.

Severity detail: CVSS 7.8 (NVD), zero-day, actively exploited (CISA KEV), known ransomware use

- Product: RARLAB WinRAR
- CVE / advisory ids: CVE-2023-38831

## Affected versions
- Before 6.23 (NVD)

## Check whether you're affected
No generic command applies (the product is a hosted service, appliance or desktop app). Check the installed version in its admin UI / About screen and compare with the versions above.

## Fix
Upgrade to one of these fixed versions (or later on the same branch):
- 6.23

After upgrading, re-run the checks above and redeploy/restart the affected services.

## Latest updates
- Oct 18, 2023: Google TAG: government-backed actors exploiting the WinRAR bug
- Aug 24, 2023: CISA adds CVE-2023-38831 to the KEV catalog
- Aug 23, 2023: Group-IB: zero-day exploited since April 2023 against traders
- Aug 2, 2023: WinRAR 6.23 released with the fix

## Advisories
- [WinRAR what's new](https://www.rarlab.com/rarnew.htm) (RARLAB)
- [NVD: CVE-2023-38831](https://nvd.nist.gov/vuln/detail/CVE-2023-38831) (NVD)
- [CISA Known Exploited Vulnerabilities Catalog](https://www.cisa.gov/known-exploited-vulnerabilities-catalog) (CISA)

## Write-ups & news
- [Traders' Dilemma: Unveiling CVE-2023-38831 WinRAR Zero-Day](https://www.group-ib.com/blog/cve-2023-38831-winrar-zero-day/)
- [Government-backed actors exploiting WinRAR vulnerability](https://blog.google/threat-analysis-group/government-backed-actors-exploiting-winrar-vulnerability/)

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Machine-readable: https://pwn.watch/i/winrar-zero-day-cve-2023-38831.json · all incidents: https://pwn.watch/incidents.json. Verify against the vendor advisory before changing production systems.