📄 ABB Cylon FLXeon 9.3.5 uukl.js Predictable Salt / Weak Hashing Algorithm

ABB Cylon FLXeon 9.3.5 (uukl.js) Predictable Salt and Weak Hashing Algorithm
    
    
    Vendor: ABB Ltd.
    Product web page: https://www.global.abb                   
    Affected version: FLXeon Series (FBXi Series, FBTi Series, FBVi Series)
                      CBX Series (FLX Series)
                      CBT Series
                      CBV Series
                      Firmware: <=9.3.5
    
    Summary: BACnet® Smart Building Controllers. ABB's BACnet portfolio features a
    series of BACnet® IP and BACnet MS/TP field controllers for ASPECT® and INTEGRA™
    building management solutions. ABB BACnet controllers are designed for intelligent
    control of HVAC equipment such as central plant, boilers, chillers, cooling towers,
    heat pump systems, air handling units (constant volume, variable air volume, and
    multi-zone), rooftop units, electrical systems such as lighting control, variable
    frequency drives and metering.
    
    The FLXeon Controller Series uses BACnet/IP standards to deliver unprecedented
    connectivity and open integration for your building automation systems. It's scalable,
    and modular, allowing you to control a diverse range of HVAC functions.
    
    Desc: The ABB Cylon FLXeon BACnet controller's /api/uukl.js module implements password
    verification and update mechanisms using the insecure MD5 hash function alongside weak
    salt generation via Math.random(). This constitutes a cryptographic vulnerability where
    password hashes are susceptible to collision and brute-force attacks due to MD5's known
    weaknesses and the low entropy of the salt. Specifically, in the verify() and change()
    functions, passwords are hashed using MD5 with predictable, non-cryptographically secure
    salts, then stored in plaintext-accessible files. This undermines the integrity of the
    authentication process, enabling attackers with file system access or knowledge of the
    implementation to precompute hash values or mount dictionary attacks.
    
    Tested on: Linux Kernel 5.4.27
               Linux Kernel 4.15.13
               NodeJS/8.4.0
               Express
    
    
    Vulnerability discovered by Gjoko 'LiquidWorm' Krstic
                                @zeroscience
    
    
    Advisory ID: ZSL-2025-5936
    Advisory URL: https://www.zeroscience.mk/en/vulnerabilities/ZSL-2025-5936.php
    
    
    21.04.2024
    
    --
    
    
    $ cat project
    
                     P   R   O   J   E   C   T
    
                            .|
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                            |'|            ._____
                    ___    |  |            |.   |' .---"|
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         .-'|  _.|  |    ||   '-__  |   |  |    ||      |
         |' | |.    |    ||       | |   |  |    ||      |
     ____|  '-'     '    ""       '-'   '-.'    '`      |____
    ░▒▓███████▓▒░░▒▓███████▓▒░ ░▒▓██████▓▒░░▒▓█▓▒░▒▓███████▓▒░  
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             ░▒▓█▓▒░░░░░░░░▒▓██████▓▒░ ░▒▓██████▓▒░
    
    
    $ sed -n '10,39p' api/uukl.js | awk '{print NR+2, $0}'
    
    10: function verify(passwd, defpwd = false) {
    11:     var pwdFileName;
    12:     if (!defpwd)
    13:         pwdFileName = pwdFile;
    14:     else
    15:         pwdFileName = defPwdFile;
    16:     const data = fs.readFileSync(pwdFileName, 'utf-8');
    17:     const split = data.toString().split(' ');
    18:     const salt = split[0];
    19:     const savedHash = split[1].trim();
    20:     const md5sum = crypto.createHash('md5');
    21:     md5sum.update(salt);
    22:     md5sum.update(passwd);
    23:     const hash = md5sum.digest('hex');
    24:     if (hash == savedHash) {
    25:         return true;
    26:     }
    27:     else {
    28:         Jrpc.doJrpc('cbxi', { method: 'uuklPwd', params: { action: 'fail' } }, (reply) => { });
    29:         return false;
    30:     }
    31: }
    32: function change(passwd) {
    33:     var md5sum = crypto.createHash('md5');
    34:     var salt = Math.floor(Math.random() * 100000).toString();
    35:     md5sum.update(salt);
    36:     md5sum.update(passwd);
    37:     var hash = md5sum.digest('hex');
    38:     fs.writeFileSync(pwdFile, salt + ' ' + hash);
    39: }