PHP LDAP get user SID

Question

I don't know how to get users unique identifier (SID) in AD. Code fragment:

...    
$filter="(&(samaccountname=".$this->username.")(memberOf:1.2.840.113556.1.4.1941:=CN=GROUP_NAME,OU=Security,DC=something,DC=something))";
    $attribute = array("cn","objectsid","description", "group", "member", "samaccountname");
    $sr=ldap_search($this->conn_ldap, $this->ldap_dn, $filter, $attribute);

    if ($sr) 
    {

    $this->info = ldap_get_entries($this->conn_ldap, $sr);
    if ($this->info["count"] == 1){

    ldap_close($this->conn_ldap);
    return true;
    }
    ... 

i can pull information with:

echo $this->info[0]["cn"][0];

or

echo $this->info[0]["objectsid"][0];

In first output i can see users name in secound something like 0�@�d^�WL7�U I believe sid should be like S-......?

Answer 1

Is old post but I do some combination what I find useful and this function is the ultimate function for binary to SID translations:

// Binary to SID
function bin_to_str_sid($binary_sid) {

    $sid = NULL;
    /* 64bt PHP */
    if(strlen(decbin(~0)) == 64)
    {
        // Get revision, indentifier, authority 
        $parts = unpack('Crev/x/nidhigh/Nidlow', $binary_sid);
        // Set revision, indentifier, authority 
        $sid = sprintf('S-%u-%d',  $parts['rev'], ($parts['idhigh']<<32) + $parts['idlow']);
        // Translate domain
        $parts = unpack('x8/V*', $binary_sid);
        // Append if parts exists
        if ($parts) $sid .= '-';
        // Join all
        $sid.= join('-', $parts);
    }
    /* 32bit PHP */
    else
    {   
        $sid = 'S-';
        $sidinhex = str_split(bin2hex($binary_sid), 2);
        // Byte 0 = Revision Level
        $sid = $sid.hexdec($sidinhex[0]).'-';
        // Byte 1-7 = 48 Bit Authority
        $sid = $sid.hexdec($sidinhex[6].$sidinhex[5].$sidinhex[4].$sidinhex[3].$sidinhex[2].$sidinhex[1]);
        // Byte 8 count of sub authorities - Get number of sub-authorities
        $subauths = hexdec($sidinhex[7]);
        //Loop through Sub Authorities
        for($i = 0; $i < $subauths; $i++) {
            $start = 8 + (4 * $i);
            // X amount of 32Bit (4 Byte) Sub Authorities
            $sid = $sid.'-'.hexdec($sidinhex[$start+3].$sidinhex[$start+2].$sidinhex[$start+1].$sidinhex[$start]);
        }
    }
    return $sid;
}

Now you can chillout and use this function in any PHP version.

Answer 2

This works on 64bit systems and I think is more succinct.

function bin_to_str_sid($binsid) {
    $parts = unpack('Crev/x/nidhigh/Nidlow', $binsid);
    $ssid = sprintf('S-%u-%d',  $parts['rev'], ($parts['idhigh']<<32) + $parts['idlow']);
    $parts = unpack('x8/V*', $binsid);
    if ($parts) $ssid .= '-';
    $ssid .= join('-', $parts);
    return $ssid;
}

Answer 3

As an alternative example, this can be done completely using PHP's unpack function. The objectSid binary structure is best documented on this MSDN doc:

Revision (1 byte): An 8-bit unsigned integer that specifies the revision level of the SID. This value MUST be set to 0x01.

SubAuthorityCount (1 byte): An 8-bit unsigned integer that specifies the number of elements in the SubAuthority array. The maximum number of elements allowed is 15.

IdentifierAuthority (6 bytes): A SID_IDENTIFIER_AUTHORITY structure that indicates the authority under which the SID was created. It describes the entity that created the SID. The Identifier Authority value {0,0,0,0,0,5} denotes SIDs created by the NT SID authority.

SubAuthority (variable): A variable length array of unsigned 32-bit integers that uniquely identifies a principal relative to the IdentifierAuthority. Its length is determined by SubAuthorityCount.

/**
 * Decode the binary SID into its readable form.
 *
 * @param string $value
 * @return string
 */
function decodeSID($value)
{
    # revision - 8bit unsigned int (C1)
    # count - 8bit unsigned int (C1)
    # 2 null bytes
    # ID - 32bit unsigned long, big-endian order
    $sid = @unpack('C1rev/C1count/x2/N1id', $value);
    $subAuthorities = [];

    if (!isset($sid['id']) || !isset($sid['rev'])) {
        throw new \UnexpectedValueException(
            'The revision level or identifier authority was not found when decoding the SID.'
        );
    }

    $revisionLevel = $sid['rev'];
    $identifierAuthority = $sid['id'];
    $subs = isset($sid['count']) ? $sid['count'] : 0;

    // The sub-authorities depend on the count, so only get as many as the count, regardless of data beyond it
    for ($i = 0; $i < $subs; $i++) {
        # Each sub-auth is a 32bit unsigned long, little-endian order
        $subAuthorities[] = unpack('V1sub', hex2bin(substr(bin2hex($value), 16 + ($i * 8), 8)))['sub'];
    }

    # Tack on the 'S-' and glue it all together...
    return 'S-'.$revisionLevel.'-'.$identifierAuthority.implode(
        preg_filter('/^/', '-', $subAuthorities)
    );
}

Answer 4

I found a solution on another website (see below). Basically this function is converter and makes SID visible:

public static function SIDtoString($ADsid)
{
   $sid = "S-";
   //$ADguid = $info[0]['objectguid'][0];
   $sidinhex = str_split(bin2hex($ADsid), 2);
   // Byte 0 = Revision Level
   $sid = $sid.hexdec($sidinhex[0])."-";
   // Byte 1-7 = 48 Bit Authority
   $sid = $sid.hexdec($sidinhex[6].$sidinhex[5].$sidinhex[4].$sidinhex[3].$sidinhex[2].$sidinhex[1]);
   // Byte 8 count of sub authorities - Get number of sub-authorities
   $subauths = hexdec($sidinhex[7]);
   //Loop through Sub Authorities
   for($i = 0; $i < $subauths; $i++) {
      $start = 8 + (4 * $i);
      // X amount of 32Bit (4 Byte) Sub Authorities
      $sid = $sid."-".hexdec($sidinhex[$start+3].$sidinhex[$start+2].$sidinhex[$start+1].$sidinhex[$start]);
   }
   return $sid;
}

https://www.null-byte.org/development/php-active-directory-ldap-authentication/