CVE-2026-8482

Executive Summary

CVE-2026-8482 is a medium-severity vulnerability (CVSS 4.3) affecting StormShield Network Security appliances running versions 4.3.0 to 4.3.41, 4.8.0 to 4.8.15, and 5.0.0 to 5.0.5. The flaw allows an authenticated attacker with SSH access (when SSH multiuser mode is enabled) to leak sensitive information, specifically the proxy CA passphrase or TPM password, by observing administration commands passed via the CLI command line tool. This is a local information disclosure vulnerability that requires prior SSH access and the multiuser mode to be active. No public exploit code or proof-of-concept is currently available, and no patch has been released by the vendor.

Supply Chain & Package Security

This vulnerability is not related to any open-source package ecosystem (NPM, PyPI, Go, Ruby). It is a proprietary appliance firmware issue.

CVSS Breakdown & Threat Level

• CVSS Score: 4.3 (Medium)
• Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
• Attack Vector: Local (AV:L) – requires SSH access to the appliance.
• Attack Complexity: Low (AC:L) – no special conditions beyond SSH access.
• Privileges Required: High (PR:H) – attacker must have valid SSH credentials.
• User Interaction: None (UI:N) – no user action required beyond the attacker’s own commands.
• Scope: Unchanged (S:U) – the vulnerability does not affect other components.
• Confidentiality Impact: High (C:H) – proxy CA passphrase or TPM password can be leaked.
• Integrity Impact: None (I:N)
• Availability Impact: None (A:N)

Threat Level: Medium. The attack surface is limited to authenticated SSH users, but the potential leakage of cryptographic secrets (proxy CA passphrase, TPM password) could lead to further compromise of encrypted communications or hardware security module integrity.

Deep Dive & Mechanics

The vulnerability resides in the CLI command line tool used for administration on StormShield Network Security appliances. When an administrator executes commands via the CLI, the command arguments (including sensitive parameters like passphrases or passwords) may be inadvertently exposed in a way that other SSH users can observe.

Root Cause: The CLI tool does not properly sanitize or mask sensitive arguments when commands are executed in a multiuser SSH session. This could be due to:

• Command history being shared or visible to other users.
• Process listing (e.g., ps) showing full command lines with arguments.
• Logging mechanisms that record command arguments in plaintext.

Attack Scenario:

1. An attacker gains SSH access to the firewall (requires valid credentials).
2. The SSH multiuser mode is enabled (allowing multiple concurrent SSH sessions).
3. An administrator runs a CLI command that includes the proxy CA passphrase or TPM password as an argument (e.g., set proxy-ca --passphrase <secret>).
4. The attacker, in another SSH session, can observe the command line via process listing (ps aux), command history, or log files, thereby extracting the secret.

Impact: Leakage of the proxy CA passphrase could allow an attacker to impersonate the firewall’s certificate authority, decrypt or forge TLS traffic. Leakage of the TPM password could compromise hardware-backed security features.

Vulnerable vs. Patched Code

No patch is currently available. The vulnerable code is in the proprietary CLI tool of StormShield Network Security. A patched version would likely:

• Mask sensitive arguments in process listings (e.g., using argv manipulation or prctl).
• Prevent command history sharing between users.
• Sanitize logs to redact sensitive parameters.

Example of vulnerable behavior (pseudocode):

# Administrator runs:
stormshield-cli set proxy-ca --passphrase MySecretPass123
# Another user sees:
ps aux | grep stormshield-cli
# Output: stormshield-cli set proxy-ca --passphrase MySecretPass123

Expected patched behavior:

# Administrator runs:
stormshield-cli set proxy-ca --passphrase ********
# Process listing shows:
stormshield-cli set proxy-ca --passphrase [REDACTED]

Exploitation & Lab Setup

Red Team

Prerequisites:

• SSH credentials for a user with access to the StormShield appliance.
• SSH multiuser mode enabled on the appliance.

Exploitation Steps:

1. SSH into the appliance as a legitimate user.
2. Monitor the system for CLI commands executed by other users:

   watch -n 1 'ps aux | grep stormshield-cli'
   

3. Alternatively, check command history files (e.g., .bash_history or appliance-specific logs):

   cat /var/log/stormshield/cli.log | grep -E '(passphrase|password)'
   

4. Extract the proxy CA passphrase or TPM password from the observed command line.

No public exploit code is available.

Blue Team

Detection:

• Monitor for multiple concurrent SSH sessions from different IPs or users.
• Alert on process listing commands (ps, top) executed by non-admin users.
• Audit CLI command logs for sensitive parameters in plaintext.

Hunting:

• Search for patterns like --passphrase or --password in command history and logs.
• Correlate SSH session times with CLI command execution times.

Lab Setup:

• Deploy a StormShield appliance in a sandboxed network.
• Enable SSH multiuser mode.
• Create two user accounts: one admin, one attacker.
• Execute a CLI command with a fake passphrase from the admin session.
• From the attacker session, attempt to observe the command line.

Indicators of Compromise (IOCs)

• Network: SSH connections to the StormShield appliance from unexpected IPs.
• Host: Presence of multiple concurrent SSH sessions.
• Process: Unauthorized users running ps, top, or w commands.
• Logs: CLI log entries containing --passphrase or --password in plaintext.
• File: Unauthorized access to /var/log/stormshield/cli.log or similar.

Detection Engineering

YARA Rule

rule CVE_2026_8482_CLI_Leak {
    meta:
        description = "Detects potential leakage of proxy CA passphrase or TPM password in StormShield CLI logs"
        author = "Valters IT"
        date = "2026-01-01"
        reference = "CVE-2026-8482"
    strings:
        $passphrase = /--passphrase\s+\S+/ nocase
        $password = /--password\s+\S+/ nocase
        $tpm = /tpm[\s_-]?password\s+\S+/ nocase
    condition:
        any of them
}

Sigma Rule

title: StormShield CLI Sensitive Argument Leak
id: cve-2026-8482-cli-leak
status: experimental
description: Detects CLI commands containing sensitive arguments (passphrase, password) that could be leaked via process listing or logs.
author: Valters IT
date: 2026/01/01
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2026-8482
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        CommandLine|contains:
            - '--passphrase'
            - '--password'
            - 'tpm_password'
    condition: selection
falsepositives:
    - Legitimate administrative use (but should be masked in patched versions)
level: medium

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET 22 (msg:"CVE-2026-8482 StormShield CLI Sensitive Leak via SSH"; flow:to_server,established; content:"stormshield-cli"; nocase; content:"--passphrase"; nocase; distance:0; within:100; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable SSH multiuser mode if not required for operations.
2. Restrict SSH access to only trusted administrators using IP whitelisting and key-based authentication.
3. Monitor CLI logs and process listings for unauthorized access.

Long-term Fix:

• Apply vendor patch when released (currently none available).
• Upgrade to a patched firmware version once published.

Workarounds:

• Use a dedicated management interface or jump host to isolate CLI commands.
• Avoid passing sensitive parameters directly in CLI commands; use interactive prompts or configuration files with restricted permissions.

Valters IT Signature This report was generated by Valters IT DevSecOps AI Assistant. For questions, contact security@valters.it.