mirror of
https://github.com/shadow1ng/fscan.git
synced 2025-09-14 14:06:44 +08:00
05727a0db7
- 新增Telnet服务插件，支持完整的Telnet协议实现和弱口令检测 - 实现Telnet连接器、利用器和主插件的完整新架构 - 支持智能服务器类型识别（无需认证、仅密码、用户名+密码） - 集成IAC命令处理、选项协商等完整Telnet协议功能 - 支持多种认证模式和用户名/密码组合暴力破解 - 完善国际化消息支持和Docker测试环境配置 - 测试验证：成功检测root:123456等弱密码组合
523 lines
12 KiB
Go
523 lines
12 KiB
Go
package telnet
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import (
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"bytes"
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"context"
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"fmt"
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"net"
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"regexp"
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"strings"
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"time"
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"github.com/shadow1ng/fscan/common"
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"github.com/shadow1ng/fscan/common/i18n"
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"github.com/shadow1ng/fscan/plugins/base"
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)
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// TelnetConnector Telnet服务连接器
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type TelnetConnector struct{}
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// NewTelnetConnector 创建新的Telnet连接器
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func NewTelnetConnector() *TelnetConnector {
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return &TelnetConnector{}
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}
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// Connect 连接到Telnet服务
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func (c *TelnetConnector) Connect(ctx context.Context, info *common.HostInfo) (interface{}, error) {
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target := fmt.Sprintf("%s:%s", info.Host, info.Ports)
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// 创建TCP连接
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conn, err := common.WrapperTcpWithContext(ctx, "tcp", target)
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if err != nil {
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return nil, fmt.Errorf(i18n.GetText("telnet_connection_failed"), err)
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}
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// 创建Telnet客户端
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client := &TelnetClient{
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IPAddr: info.Host,
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Port: info.Ports,
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conn: conn,
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}
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// 初始化连接
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client.init()
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return client, nil
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}
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// Authenticate 认证Telnet服务
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func (c *TelnetConnector) Authenticate(ctx context.Context, conn interface{}, cred *base.Credential) error {
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client, ok := conn.(*TelnetClient)
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if !ok {
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return fmt.Errorf("invalid connection type")
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}
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// 检查上下文是否已取消
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select {
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case <-ctx.Done():
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return ctx.Err()
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default:
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}
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// 设置凭据
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client.UserName = cred.Username
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client.Password = cred.Password
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// 判断服务器类型
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client.ServerType = client.MakeServerType()
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// 处理无需认证的情况
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if client.ServerType == UnauthorizedAccess {
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return nil // 认证成功
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}
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// 尝试登录
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return client.Login()
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}
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// Close 关闭连接
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func (c *TelnetConnector) Close(conn interface{}) error {
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if client, ok := conn.(*TelnetClient); ok && client != nil {
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client.Close()
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}
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return nil
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}
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// TelnetClient Telnet客户端结构体
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type TelnetClient struct {
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IPAddr string // 服务器IP地址
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Port string // 服务器端口
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UserName string // 用户名
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Password string // 密码
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conn net.Conn // 网络连接
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LastResponse string // 最近一次响应内容
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ServerType int // 服务器类型
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}
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// init 初始化Telnet连接
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func (c *TelnetClient) init() {
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// 启动后台goroutine处理服务器响应
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go func() {
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for {
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// 读取服务器响应
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buf, err := c.read()
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if err != nil {
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// 处理连接关闭和EOF情况
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if strings.Contains(err.Error(), "closed") ||
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strings.Contains(err.Error(), "EOF") {
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break
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}
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break
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}
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// 处理响应数据
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displayBuf, commandList := c.SerializationResponse(buf)
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if len(commandList) > 0 {
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// 有命令需要回复
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replyBuf := c.MakeReplyFromList(commandList)
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c.LastResponse += string(displayBuf)
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_ = c.write(replyBuf)
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} else {
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// 仅保存显示内容
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c.LastResponse += string(displayBuf)
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}
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}
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}()
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// 等待连接初始化完成
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time.Sleep(time.Second * 2)
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}
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// WriteContext 写入数据到Telnet连接
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func (c *TelnetClient) WriteContext(s string) {
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// 写入字符串并添加回车及空字符
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_ = c.write([]byte(s + "\x0d\x00"))
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}
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// ReadContext 读取Telnet连接返回的内容
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func (c *TelnetClient) ReadContext() string {
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// 读取完成后清空缓存
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defer func() { c.Clear() }()
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// 等待响应
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if c.LastResponse == "" {
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time.Sleep(time.Second)
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}
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// 处理特殊字符
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c.LastResponse = strings.ReplaceAll(c.LastResponse, "\x0d\x00", "")
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c.LastResponse = strings.ReplaceAll(c.LastResponse, "\x0d\x0a", "\n")
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return c.LastResponse
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}
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// Close 关闭Telnet连接
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func (c *TelnetClient) Close() {
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if c.conn != nil {
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c.conn.Close()
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}
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}
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// SerializationResponse 解析Telnet响应数据
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func (c *TelnetClient) SerializationResponse(responseBuf []byte) (displayBuf []byte, commandList [][]byte) {
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for {
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// 查找IAC命令标记
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index := bytes.IndexByte(responseBuf, IAC)
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if index == -1 || len(responseBuf)-index < 2 {
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displayBuf = append(displayBuf, responseBuf...)
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break
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}
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// 获取选项字符
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ch := responseBuf[index+1]
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// 处理连续的IAC
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if ch == IAC {
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displayBuf = append(displayBuf, responseBuf[:index]...)
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responseBuf = responseBuf[index+1:]
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continue
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}
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// 处理DO/DONT/WILL/WONT命令
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if ch == DO || ch == DONT || ch == WILL || ch == WONT {
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commandBuf := responseBuf[index : index+3]
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commandList = append(commandList, commandBuf)
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displayBuf = append(displayBuf, responseBuf[:index]...)
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responseBuf = responseBuf[index+3:]
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continue
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}
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// 处理子协商命令
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if ch == SB {
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displayBuf = append(displayBuf, responseBuf[:index]...)
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seIndex := bytes.IndexByte(responseBuf, SE)
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if seIndex != -1 && seIndex > index {
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commandList = append(commandList, responseBuf[index:seIndex+1])
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responseBuf = responseBuf[seIndex+1:]
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continue
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}
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}
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break
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}
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return displayBuf, commandList
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}
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// MakeReplyFromList 处理命令列表并生成回复
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func (c *TelnetClient) MakeReplyFromList(list [][]byte) []byte {
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var reply []byte
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for _, command := range list {
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reply = append(reply, c.MakeReply(command)...)
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}
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return reply
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}
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// MakeReply 根据命令生成对应的回复
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func (c *TelnetClient) MakeReply(command []byte) []byte {
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// 命令至少需要3字节
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if len(command) < 3 {
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return []byte{}
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}
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verb := command[1] // 动作类型
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option := command[2] // 选项码
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// 处理回显(ECHO)和抑制继续进行(SGA)选项
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if option == ECHO || option == SGA {
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switch verb {
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case DO:
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return []byte{IAC, WILL, option}
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case DONT:
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return []byte{IAC, WONT, option}
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case WILL:
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return []byte{IAC, DO, option}
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case WONT:
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return []byte{IAC, DONT, option}
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case SB:
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// 处理子协商命令
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if len(command) >= 4 {
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modifier := command[3]
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if modifier == ECHO {
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return []byte{IAC, SB, option, BINARY, IAC, SE}
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}
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}
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}
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} else {
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// 处理其他选项 - 拒绝所有请求
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switch verb {
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case DO, DONT:
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return []byte{IAC, WONT, option}
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case WILL, WONT:
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return []byte{IAC, DONT, option}
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}
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}
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return []byte{}
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}
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// read 从Telnet连接读取数据
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func (c *TelnetClient) read() ([]byte, error) {
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var buf [2048]byte
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// 设置读取超时为2秒
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_ = c.conn.SetReadDeadline(time.Now().Add(time.Second * 2))
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n, err := c.conn.Read(buf[0:])
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if err != nil {
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return nil, err
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}
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return buf[:n], nil
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}
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// write 向Telnet连接写入数据
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func (c *TelnetClient) write(buf []byte) error {
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// 设置写入超时
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_ = c.conn.SetWriteDeadline(time.Now().Add(time.Second * 3))
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_, err := c.conn.Write(buf)
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if err != nil {
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return err
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}
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// 写入后短暂延迟，让服务器有时间处理
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time.Sleep(TIME_DELAY_AFTER_WRITE)
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return nil
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}
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// Login 根据服务器类型执行登录
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func (c *TelnetClient) Login() error {
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switch c.ServerType {
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case Closed:
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return fmt.Errorf("service is disabled")
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case UnauthorizedAccess:
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return nil
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case OnlyPassword:
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return c.LogBaserOnlyPassword()
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case UsernameAndPassword:
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return c.LogBaserUsernameAndPassword()
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default:
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return fmt.Errorf("unknown server type")
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}
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}
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// MakeServerType 通过分析服务器响应判断服务器类型
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func (c *TelnetClient) MakeServerType() int {
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responseString := c.ReadContext()
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// 空响应情况
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if responseString == "" {
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return Closed
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}
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response := strings.Split(responseString, "\n")
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if len(response) == 0 {
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return Closed
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}
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lastLine := strings.ToLower(response[len(response)-1])
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// 检查是否需要用户名和密码
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if containsAny(lastLine, []string{"user", "name", "login", "account", "用户名", "登录"}) {
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return UsernameAndPassword
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}
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// 检查是否只需要密码
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if strings.Contains(lastLine, "pass") {
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return OnlyPassword
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}
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// 检查是否无需认证的情况
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if isNoAuthRequired(lastLine) || c.isLoginSucceed(responseString) {
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return UnauthorizedAccess
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}
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return Closed
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}
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// LogBaserOnlyPassword 处理只需密码的登录
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func (c *TelnetClient) LogBaserOnlyPassword() error {
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c.Clear() // 清空之前的响应
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// 发送密码并等待响应
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c.WriteContext(c.Password)
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time.Sleep(time.Second * 2)
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// 验证登录结果
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responseString := c.ReadContext()
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if c.isLoginFailed(responseString) {
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return fmt.Errorf("login failed")
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}
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if c.isLoginSucceed(responseString) {
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return nil
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}
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return fmt.Errorf("login failed")
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}
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// LogBaserUsernameAndPassword 处理需要用户名和密码的登录
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func (c *TelnetClient) LogBaserUsernameAndPassword() error {
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// 发送用户名
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c.WriteContext(c.UserName)
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time.Sleep(time.Second * 2)
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c.Clear()
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// 发送密码
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c.WriteContext(c.Password)
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time.Sleep(time.Second * 3)
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// 验证登录结果
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responseString := c.ReadContext()
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if c.isLoginFailed(responseString) {
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return fmt.Errorf("login failed")
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}
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if c.isLoginSucceed(responseString) {
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return nil
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}
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return fmt.Errorf("login failed")
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}
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// Clear 清空最近一次响应
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func (c *TelnetClient) Clear() {
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c.LastResponse = ""
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}
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// 登录失败的关键词列表
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var loginFailedString = []string{
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"wrong",
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"invalid",
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"fail",
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"incorrect",
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"error",
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}
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// isLoginFailed 检查是否登录失败
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func (c *TelnetClient) isLoginFailed(responseString string) bool {
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responseString = strings.ToLower(responseString)
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// 空响应视为失败
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if responseString == "" {
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return true
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}
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// 检查失败关键词
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for _, str := range loginFailedString {
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if strings.Contains(responseString, str) {
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return true
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}
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}
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// 检查是否仍在要求输入凭证
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patterns := []string{
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"(?is).*pass(word)?:$",
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"(?is).*user(name)?:$",
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"(?is).*login:$",
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}
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for _, pattern := range patterns {
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if regexp.MustCompile(pattern).MatchString(responseString) {
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return true
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}
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}
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return false
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}
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// isLoginSucceed 检查是否登录成功
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func (c *TelnetClient) isLoginSucceed(responseString string) bool {
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// 空响应视为失败
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if responseString == "" {
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return false
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}
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// 获取最后一行响应
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lines := strings.Split(responseString, "\n")
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if len(lines) == 0 {
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return false
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}
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lastLine := lines[len(lines)-1]
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// 检查命令提示符
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if regexp.MustCompile("^[#$>].*").MatchString(lastLine) ||
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regexp.MustCompile("^<[a-zA-Z0-9_]+>.*").MatchString(lastLine) {
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return true
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}
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// 检查last login信息
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if regexp.MustCompile("(?:s)last login").MatchString(responseString) {
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return true
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}
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// 发送测试命令验证
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c.Clear()
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c.WriteContext("?")
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time.Sleep(time.Second * 2)
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responseString = c.ReadContext()
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// 检查响应长度
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if strings.Count(responseString, "\n") > 6 || len([]rune(responseString)) > 100 {
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return true
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}
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return false
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}
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// 辅助函数：检查字符串是否包含任意给定子串
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func containsAny(s string, substrings []string) bool {
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for _, sub := range substrings {
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if strings.Contains(s, sub) {
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return true
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}
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}
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return false
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}
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// 辅助函数：检查是否无需认证
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func isNoAuthRequired(line string) bool {
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patterns := []string{
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`^/ #.*`,
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`^<[A-Za-z0-9_]+>`,
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`^#`,
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}
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for _, pattern := range patterns {
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if regexp.MustCompile(pattern).MatchString(line) {
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return true
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}
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}
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return false
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}
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// Telnet协议常量定义
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const (
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// 写入操作后的延迟时间
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TIME_DELAY_AFTER_WRITE = 300 * time.Millisecond
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// Telnet基础控制字符
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IAC = byte(255) // 解释为命令(Interpret As Command)
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DONT = byte(254) // 请求对方停止执行某选项
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DO = byte(253) // 请求对方执行某选项
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WONT = byte(252) // 拒绝执行某选项
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WILL = byte(251) // 同意执行某选项
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// 子协商相关控制字符
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SB = byte(250) // 子协商开始(Subnegotiation Begin)
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SE = byte(240) // 子协商结束(Subnegotiation End)
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// 特殊功能字符
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NULL = byte(0) // 空字符
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EOF = byte(236) // 文档结束
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SUSP = byte(237) // 暂停进程
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ABORT = byte(238) // 停止进程
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REOR = byte(239) // 记录结束
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// Telnet选项代码
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BINARY = byte(0) // 8位数据通道
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ECHO = byte(1) // 回显
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SGA = byte(3) // 禁止继续
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// 服务器类型常量定义
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Closed = iota // 连接关闭
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UnauthorizedAccess // 无需认证
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OnlyPassword // 仅需密码
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UsernameAndPassword // 需要用户名和密码
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) |