# CVE-2023-3347: Samba: smb2 packet signing is not enforced when "server signing = required" is set > Attackers can bypass SMB2 packet signing enforcement to perform man-in-the-middle attacks and modify data in transit. - **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 20 Jul 2023 - **Updated:** 20 Nov 2025 - **Also known as:** ALSA-2023:4325, ALSA-2023:4328, AZL-48166, DEBIAN-CVE-2023-3347, ECHO-aaa9-06cc-7b7a, GHSA-m82c-5hpw-48f7, RHSA-2023:4325, RHSA-2023:4328 ## What is CVE-2023-3347? CVE-2023-3347 is a medium-severity vulnerability in Fedoraproject Fedora, published on 20 Jul 2023. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description A vulnerability was found in Samba's SMB2 packet signing mechanism. The SMB2 packet signing is not enforced if an admin configured "server signing = required" or for SMB2 connections to Domain Controllers where SMB2 packet signing is mandatory. This flaw allows an attacker to perform attacks, such as a man-in-the-middle attack, by intercepting the network traffic and modifying the SMB2 messages between client and server, affecting the integrity of the data. Weakness: CWE-924 (Improper Enforcement of Message Integrity During Transmission in a Communication Channel), CWE-347 (Improper Verification of Cryptographic Signature) ## Which versions are affected by CVE-2023-3347? It affects 4 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `ctdb` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `libnetapi` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `libnetapi-devel` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `libsmbclient` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `libsmbclient-devel` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `libwbclient` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `libwbclient-devel` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `python3-samba` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `python3-samba-dc` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `python3-samba-devel` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `python3-samba-test` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-client` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-client-libs` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-common` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-common-libs` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-common-tools` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-dc-libs` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-dcerpc` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-devel` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-krb5-printing` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-ldb-ldap-modules` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-libs` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-pidl` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-test` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-test-libs` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-tools` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-usershares` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-vfs-iouring` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-winbind` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-winbind-clients` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-winbind-krb5-locator` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-winbind-modules` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `samba-winexe` | AlmaLinux:8 | All versions | 4.17.5-3.el8_8.alma | | `ctdb` | AlmaLinux:9 | All versions | 4.17.5-103.el9_2.alma | | `libnetapi` | AlmaLinux:9 | All versions | 4.17.5-103.el9_2.alma | | `libnetapi-devel` | AlmaLinux:9 | All versions | 4.17.5-103.el9_2.alma | | `libsmbclient` | AlmaLinux:9 | All versions | 4.17.5-103.el9_2.alma | | `libsmbclient-devel` | AlmaLinux:9 | All versions | 4.17.5-103.el9_2.alma | | `libwbclient` | AlmaLinux:9 | All versions | 4.17.5-103.el9_2.alma | Products: Fedoraproject Fedora, Redhat Enterprise Linux, Redhat Storage, Samba Samba. ## How do I fix CVE-2023-3347? Apply the vendor's patch. ## Is CVE-2023-3347 being exploited? There is no known exploitation of CVE-2023-3347 in the wild and no public exploit code. ## Other vulnerabilities in Fedoraproject Fedora - [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild) - [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild) - [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild) - [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild) - [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2023-3347 and fix it if it is affected. What it is: CVE-2023-3347 is a medium-severity vulnerability in Fedoraproject Fedora, published on 20 Jul 2023. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2023-3347 in the wild and no public exploit code. Affected product: Fedoraproject Fedora. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2023-3347/ (Markdown: https://insights.sbomify.com/CVE-2023-3347/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2023-3347 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-3347 - OSV: https://osv.dev/vulnerability/CVE-2023-3347 --- From sbomify Insights: https://insights.sbomify.com/CVE-2023-3347/ Summaries are generated and may contain mistakes; the official description above is the record.