「有人試圖劫持加密連線」錯誤是什麼意思？

簡介

本文檔介紹錯誤「可能是有人試圖劫持到遠端主機的加密連線」，以及針對思科郵件安全裝置(ESA)和思科安全管理裝置(SMA)採取的糾正步驟。

「有人試圖劫持加密連線」錯誤是什麼意思？

在配置與SMA的ESA通訊時，可能會看到以下錯誤：

Error - The host key for 172.16.6.165 appears to have changed.
It is possible that someone is trying to hijack the encrypted 
connection to the remote host. 
Please use the logconfig->hostkeyconfig command to verify 
(and possibly update) the SSH host key for 172.16.6.165.

更換ESA並使用與原始ESA相同的主機名和/或IP地址時，可能會發生這種情況。先前儲存的SSH金鑰儲存在SMA上，用於ESA和SMA之間的通訊和身份驗證。然後，SMA發現ESA通訊路徑已更改，並且相信一個未經授權的源現在控制著與ESA相關聯的IP地址。

要更正此問題，請登入SMA的CLI，並完成以下步驟：

1. 輸入logconfig命令。
2. 輸入hostkeyconfig。
3. 輸入delete並選擇當前安裝的ESA IP主機金鑰清單中關聯的數字。
4. 返回主CLI提示符並輸入commit命令。

mysma.local> logconfig

Currently configured logs:
 Log Name Log Type Retrieval Interval 
 ---------------------------------------------------------------------------------
 1. authentication Authentication Logs FTP Poll None 
 2. backup_logs Backup Logs FTP Poll None 
 3. cli_logs CLI Audit Logs FTP Poll None 
 4. euq_logs Spam Quarantine Logs FTP Poll None 
 5. euqgui_logs Spam Quarantine GUI Logs FTP Poll None 
 6. ftpd_logs FTP Server Logs FTP Poll None 
 7. gui_logs HTTP Logs FTP Poll None 
 8. haystackd_logs Haystack Logs FTP Poll None 
 9. ldap_logs LDAP Debug Logs FTP Poll None 
10. mail_logs Cisco Text Mail Logs FTP Poll None 
11. reportd_logs Reporting Logs FTP Poll None 
12. reportqueryd_logs Reporting Query Logs FTP Poll None 
13. slbld_logs Safe/Block Lists Logs FTP Poll None 
14. smad_logs SMA Logs FTP Poll None 
15. snmp_logs SNMP Logs FTP Poll None 
16. sntpd_logs NTP logs FTP Poll None 
17. system_logs System Logs FTP Poll None 
18. trackerd_logs Tracking Logs FTP Poll None 
19. updater_logs Updater Logs FTP Poll None 
20. upgrade_logs Upgrade Logs FTP Poll None 

Choose the operation you want to perform:
- NEW - Create a new log.
- EDIT - Modify a log subscription.
- DELETE - Remove a log subscription.
- SETUP - General settings.
- LOGHEADERS - Configure headers to log.
- HOSTKEYCONFIG - Configure SSH host keys.
[]> hostkeyconfig

Currently installed host keys:
1. 172.16.6.165 ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA0ilM...DVc7plDQ== 
2. 172.16.6.150 ssh-dss AAAAB3NzaC1kc3MAAACBAODKHq6uakiM...cooFXzLHFP 
3. 172.16.6.131 ssh-dss AAAAB3NzaC1kc3MAAACBAI4LkblFtidp...WhM5XLNA== 


Choose the operation you want to perform:
- NEW - Add a new key.
- EDIT - Modify a key.
- DELETE - Remove a key.
- SCAN - Automatically download a host key.
- PRINT - Display a key.
- HOST - Display system host keys.
- FINGERPRINT - Display system host key fingerprints.
- USER - Display system user keys.
[]> delete

Enter the number of the key you wish to delete.
[]> 1

Currently installed host keys:
1. 172.16.6.150 ssh-dss AAAAB3NzaC1kc3MAAACBAODKHq6uakiM...cooFXzLHFP 
2. 172.16.6.131 ssh-dss AAAAB3NzaC1kc3MAAACBAI4LkblFtidp...WhM5XLNA== 

Choose the operation you want to perform:
- NEW - Create a new log.
- EDIT - Modify a log subscription.
- DELETE - Remove a log subscription.
- SETUP - General settings.
- LOGHEADERS - Configure headers to log.
- HOSTKEYCONFIG - Configure SSH host keys.
[]> 

Currently configured logs:
 Log Name Log Type Retrieval Interval 
 ---------------------------------------------------------------------------------
 1. authentication Authentication Logs FTP Poll None 
 2. backup_logs Backup Logs FTP Poll None 
 3. cli_logs CLI Audit Logs FTP Poll None 
 4. euq_logs Spam Quarantine Logs FTP Poll None 
 5. euqgui_logs Spam Quarantine GUI Logs FTP Poll None 
 6. ftpd_logs FTP Server Logs FTP Poll None 
 7. gui_logs HTTP Logs FTP Poll None 
 8. haystackd_logs Haystack Logs FTP Poll None 
 9. ldap_logs LDAP Debug Logs FTP Poll None 
10. mail_logs Cisco Text Mail Logs FTP Poll None 
11. reportd_logs Reporting Logs FTP Poll None 
12. reportqueryd_logs Reporting Query Logs FTP Poll None 
13. slbld_logs Safe/Block Lists Logs FTP Poll None 
14. smad_logs SMA Logs FTP Poll None 
15. snmp_logs SNMP Logs FTP Poll None 
16. sntpd_logs NTP logs FTP Poll None 
17. system_logs System Logs FTP Poll None 
18. trackerd_logs Tracking Logs FTP Poll None 
19. updater_logs Updater Logs FTP Poll None 
20. upgrade_logs Upgrade Logs FTP Poll None 

mysma.local> commit

Please enter some comments describing your changes:
[]> ssh key update 

最後，從SMA GUI中選擇Centralized Services > Security Appliances，然後選擇清單中顯示原始錯誤的ESA。 選擇建立連線……和測試連線後，它將進行身份驗證、建立新的SSH主機金鑰對，並將此主機金鑰對儲存在SMA上。  

重新訪問SMA的CLI，並重新運行logconfig > hostkeyconfig以檢視新的主機金鑰對。

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