CVE-2023-42464 – A Type Confusion vulnerability in Netatalk's af... (How to Fix)

Q: What is the severity of CVE-2023-42464?

CVE-2023-42464 has a CVSS score of 9.8 (CRITICAL). A Type Confusion vulnerability in Netatalk's afpd service allows remote attackers to potentially execute arbitrary code by sending malicious Spotlight RPC packets. This affects Netatalk 3.1.x versions before 3.1.17 when the Spotlight feature is enabled. Organizations using Netatalk for Apple Filing Protocol services are at risk.

📋 TL;DR

A Type Confusion vulnerability in Netatalk's afpd service allows remote attackers to potentially execute arbitrary code by sending malicious Spotlight RPC packets. This affects Netatalk 3.1.x versions before 3.1.17 when the Spotlight feature is enabled. Organizations using Netatalk for Apple Filing Protocol services are at risk.

💻 Affected Systems

Products:

Netatalk

Versions: 3.1.x before 3.1.17

Operating Systems: Linux, Unix-like systems running Netatalk

Default Config Vulnerable: ✅ No

Notes: Only vulnerable when Spotlight RPC functionality is enabled in afpd configuration (Spotlight support is optional).

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution with root privileges leading to complete system compromise, data theft, and persistent backdoor installation.

🟠

Likely Case

Remote code execution with the privileges of the afpd process (often running as root or a privileged user), allowing system takeover and lateral movement.

🟢

If Mitigated

Denial of service or limited information disclosure if exploit attempts are blocked or fail.

🌐 Internet-Facing: HIGH - Netatalk services exposed to the internet are directly vulnerable to remote exploitation without authentication.

🏢 Internal Only: HIGH - Internal attackers or compromised systems can exploit this vulnerability to gain privileged access to Netatalk servers.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires crafting malicious Spotlight RPC packets but no authentication is needed. Similar to CVE-2023-34967 which had public exploit code.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 3.1.17

Vendor Advisory: https://netatalk.io/security/CVE-2023-42464

Restart Required: Yes

Instructions:

1. Download Netatalk 3.1.17 from official sources. 2. Stop afpd service. 3. Install/upgrade to version 3.1.17. 4. Restart afpd service.

🔧 Temporary Workarounds

Disable Spotlight RPC

linux

Disable Spotlight functionality in afpd configuration to remove the vulnerable code path.

Edit afpd.conf and set 'spotlight = no' or remove Spotlight-related configuration

Network Segmentation

linux

Restrict access to Netatalk services (TCP/UDP 548, 427) to trusted networks only.

iptables -A INPUT -p tcp --dport 548 -s TRUSTED_NET -j ACCEPT
iptables -A INPUT -p tcp --dport 548 -j DROP

🧯 If You Can't Patch

Disable Spotlight RPC functionality in afpd configuration immediately
Implement strict network access controls to limit exposure to Netatalk services

🔍 How to Verify

Check if Vulnerable:

Check Netatalk version: 'afpd -v' or 'netatalk -v'. If version is 3.1.x and < 3.1.17, and Spotlight is enabled, system is vulnerable.

Check Version:

afpd -v 2>/dev/null || netatalk -v 2>/dev/null || dpkg -l | grep netatalk || rpm -qa | grep netatalk

Verify Fix Applied:

Verify version is 3.1.17 or higher: 'afpd -v' should show 3.1.17+. Check afpd.conf to ensure Spotlight is disabled if not needed.

📡 Detection & Monitoring

Log Indicators:

Unusual Spotlight RPC requests in afpd logs
Multiple failed Spotlight queries from single source
Process crashes or abnormal afpd restarts

Network Indicators:

Unusual traffic to TCP/UDP port 548 (AFP) or 427 (SLP)
Spike in Spotlight RPC packets
Malformed RPC packets to Netatalk services

SIEM Query:

source="afpd.log" AND ("spotlight" OR "RPC") AND (error OR fail OR crash)

📊 Metadata

CVE ID: CVE-2023-42464

CVSS v3 Score: 9.8 (CRITICAL)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE: CWE-843

Published: September 20, 2023

Last Updated: November 21, 2024

🔗 References

https://github.com/Netatalk/netatalk/issues/486 Issue Tracking,Patch,Vendor Advisory
https://lists.debian.org/debian-lts-announce/2023/09/msg00031.html Mailing List,Third Party Advisory
https://netatalk.io/security/CVE-2023-42464
https://netatalk.sourceforge.io/ Product
https://netatalk.sourceforge.io/3.1/htmldocs/afpd.8.html Product
https://netatalk.sourceforge.io/CVE-2023-42464.php Patch,Vendor Advisory
https://www.debian.org/security/2023/dsa-5503 Third Party Advisory
https://github.com/Netatalk/netatalk/issues/486 Issue Tracking,Patch,Vendor Advisory
https://lists.debian.org/debian-lts-announce/2023/09/msg00031.html Mailing List,Third Party Advisory
https://netatalk.io/security/CVE-2023-42464
https://netatalk.sourceforge.io/ Product
https://netatalk.sourceforge.io/3.1/htmldocs/afpd.8.html Product
https://netatalk.sourceforge.io/CVE-2023-42464.php Patch,Vendor Advisory
https://www.debian.org/security/2023/dsa-5503 Third Party Advisory

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