CVE-2024-5262: Interactsh Information Disclosure Flaw

CVE-2024-5262 Overview

CVE-2024-5262 is a Files or Directories Accessible to External Parties vulnerability affecting the SMB server component in ProjectDiscovery Interactsh. This critical security flaw allows remote attackers to read and write arbitrary files within the directory and subdirectories where the victim runs interactsh-server through anonymous login capabilities.

Interactsh is an open-source tool designed for out-of-band interaction gathering, commonly used by security researchers and penetration testers for vulnerability detection. The vulnerability in its SMB server implementation creates a severe security risk by enabling unauthenticated file system access.

Critical Impact

Remote attackers can exploit anonymous SMB login to gain unauthorized read/write access to sensitive files on servers running Interactsh, potentially leading to data theft, configuration manipulation, or further system compromise.

Affected Products

• ProjectDiscovery Interactsh (all versions prior to patch)
• Interactsh SMB Server component
• Self-hosted Interactsh deployments with SMB protocol enabled

Discovery Timeline

• 2024-06-05 - CVE-2024-5262 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2024-5262

Vulnerability Analysis

This vulnerability is classified under CWE-552 (Files or Directories Accessible to External Parties), indicating an improper access control implementation in the Interactsh SMB server. The flaw exists because the SMB server component does not properly restrict anonymous authentication, allowing any remote attacker to connect without credentials and access the file system.

The impact is severe as it provides attackers with the ability to both read sensitive configuration files, logs, and potentially credentials stored on the server, as well as write malicious files that could be used for further exploitation or persistence mechanisms.

Root Cause

The root cause of CVE-2024-5262 lies in the SMB server's misconfigured authentication handling. The Interactsh SMB server component fails to enforce proper authentication requirements, defaulting to or allowing anonymous login connections. This design flaw effectively treats all SMB connections as trusted, bypassing standard authentication controls that would normally prevent unauthorized file system access.

Attack Vector

The attack can be executed remotely over the network without any authentication requirements. An attacker can exploit this vulnerability by:

1. Identifying a target running Interactsh server with the SMB protocol enabled
2. Initiating an anonymous SMB connection to the server
3. Browsing the exposed directory structure without credentials
4. Reading sensitive files including configuration, logs, and potentially credentials
5. Writing malicious files to achieve persistence or further compromise

The vulnerability requires no user interaction and can be exploited by anyone with network access to the affected SMB port.

Detection Methods for CVE-2024-5262

Indicators of Compromise

• Unexpected anonymous SMB connections to the Interactsh server
• Unusual file access patterns in the Interactsh server directory
• Creation of unfamiliar files in the server's working directory
• SMB authentication logs showing successful anonymous logins
• Modifications to configuration files without administrator action

Detection Strategies

• Monitor SMB connection logs for anonymous authentication attempts to the Interactsh server
• Implement network monitoring rules to detect SMB traffic targeting Interactsh server ports
• Use file integrity monitoring (FIM) to detect unauthorized changes to Interactsh server directories
• Deploy intrusion detection signatures for anomalous SMB access patterns
• Review authentication logs for null session or anonymous login events

Monitoring Recommendations

• Enable detailed SMB audit logging on systems running Interactsh
• Configure SIEM alerts for anonymous SMB connections from external IP addresses
• Monitor for large file transfers or unusual read/write operations via SMB
• Track file system changes in the Interactsh server directory using endpoint detection tools

How to Mitigate CVE-2024-5262

Immediate Actions Required

• Update Interactsh to the patched version that addresses the anonymous login vulnerability
• Disable the SMB server component if not required for your use case
• Restrict network access to the Interactsh SMB port using firewall rules
• Audit file systems for evidence of unauthorized access or malicious file creation
• Review and rotate any credentials that may have been exposed on affected servers

Patch Information

ProjectDiscovery has addressed this vulnerability through Pull Request #874 on their GitHub repository. Users should update to the latest version of Interactsh that includes this fix. Additional details about the vulnerability can be found in the Zuso Security Advisory ZA-2024-01.

Workarounds

• Disable the SMB server protocol in Interactsh configuration until patching is possible
• Implement network segmentation to isolate Interactsh servers from untrusted networks
• Use firewall rules to block external access to SMB ports (typically 445/TCP)
• Run Interactsh in a containerized environment with restricted file system access
• Deploy a reverse proxy with authentication in front of the Interactsh SMB service

# Example: Block external SMB access using iptables
iptables -A INPUT -p tcp --dport 445 -s 192.168.0.0/16 -j ACCEPT
iptables -A INPUT -p tcp --dport 445 -j DROP

# Example: Disable SMB in Interactsh startup
# Start interactsh-server without SMB protocol
interactsh-server -smb=false