安全 : Cisco IronPort Email 安全设备

“潜在的目录收获攻击检测的”警告消息是什么意思?

2016 年 10 月 27 日 - 机器翻译
其他版本: PDFpdf | 英语 (2015 年 8 月 22 日) | 反馈

简介

本文在思科电子邮件安全工具(ESA)描述“潜在的目录收获攻击”错误消息如接收。

贡献用马克Strasheim和罗伯特Sherwin, Cisco TAC工程师。

 

“潜在的目录收获攻击检测的”警告消息是什么意思?

ESA的管理员接收以下目录收获攻击预防(DHAP)警告消息:

The Warning message is:

Potential Directory Harvest Attack detected. See the system mail logs for more
information about this attack.

Version: 8.0.1-023
Serial Number: XXBAD1112DYY-008X011
Timestamp: 22 Sep 2014 21:21:32 -0600

这些警报被认为信息性,并且您不应该需要采取任何行动。外部邮件服务器尝试了许多无效收件人并且触发了DHAP (目录收获攻击预防)警报。ESA作为已配置的根据邮件策略配置。  

这是无效收件人最大每个监听程序从远程主机将接收的小时。此阈值代表RATS拒绝和SMTP呼叫向前与消息总数一起的服务器拒绝总数到在工作队列丢弃在SMTP会话或重新启动的无效LDAP收件人(如LDAP所配置的一样请接受在相关的监听程序的设置)。关于配置LDAP的DHAP的更多信息请接受查询,参见“LDAP查询”电子邮件安全用户指南的章节。 

如果不希望收到这些警报,您能调节您与alertconfig的提醒的配置文件过滤掉这些:

myesa.local> alertconfig

Sending alerts to:
robert@domain.com
Class: All - Severities: All

Initial number of seconds to wait before sending a duplicate alert: 300
Maximum number of seconds to wait before sending a duplicate alert: 3600
Maximum number of alerts stored in the system are: 50

Alerts will be sent using the system-default From Address.

Cisco IronPort AutoSupport: Enabled
You will receive a copy of the weekly AutoSupport reports.

Choose the operation you want to perform:
- NEW - Add a new email address to send alerts.
- EDIT - Modify alert subscription for an email address.
- DELETE - Remove an email address.
- CLEAR - Remove all email addresses (disable alerts).
- SETUP - Configure alert settings.
- FROM - Configure the From Address of alert emails.
[]> edit

Please select the email address to edit.
1. robert@domain.com (all)
[]> 1

Choose the Alert Class to modify for "robert@domain.com".
Press Enter to return to alertconfig.
1. All - Severities: All
2. System - Severities: All
3. Hardware - Severities: All
4. Updater - Severities: All
5. Outbreak Filters - Severities: All
6. Anti-Virus - Severities: All
7. Anti-Spam - Severities: All
8. Directory Harvest Attack Prevention - Severities: All

或者从GUI系统管理>警告>接收地址并且修改接收的严重性的或者警告全文。  

GUI

要查看您的从GUI的DHAP配置参数,通过邮件策略>邮件流量策略单击>点击策略名称编辑或者默认策略参数>和做对邮件流量限额/目录的变动收获攻击预防(DHAP)部分当必要时:

提交并且确认您的对GUI的更改。

CLI

要查看您的从CLI的DHAP配置参数,请使用listenerconfig > Edit (选择监听程序的编号编辑) >编辑DHAP设置的hostaccess >默认

Default Policy Parameters
==========================
Maximum Message Size: 10M
Maximum Number Of Concurrent Connections From A Single IP: 10
Maximum Number Of Messages Per Connection: 10
Maximum Number Of Recipients Per Message: 50
Directory Harvest Attack Prevention: Enabled
Maximum Number Of Invalid Recipients Per Hour: 25
Maximum Number Of Recipients Per Hour: Disabled
Maximum Number of Recipients per Envelope Sender: Disabled
Use SenderBase for Flow Control: Yes
Spam Detection Enabled: Yes
Virus Detection Enabled: Yes
Allow TLS Connections: No
Allow SMTP Authentication: No
Require TLS To Offer SMTP authentication: No
DKIM/DomainKeys Signing Enabled: No
DKIM Verification Enabled: No
SPF/SIDF Verification Enabled: No
DMARC Verification Enabled: No
Envelope Sender DNS Verification Enabled: No
Domain Exception Table Enabled: No
Accept untagged bounces: No

There are currently 5 policies defined.
There are currently 8 sender groups.

Choose the operation you want to perform:
- NEW - Create a new entry.
- EDIT - Modify an entry.
- DELETE - Remove an entry.
- MOVE - Move an entry.
- DEFAULT - Set the defaults.
- PRINT - Display the table.
- IMPORT - Import a table from a file.
- EXPORT - Export the table to a file.
- RESET - Remove senders and set policies to system default.
[]> default

Enter the default maximum message size. Add a trailing k for kilobytes, M for
megabytes, or no letter for bytes.
[10M]>

Enter the maximum number of concurrent connections allowed from a single
IP address.
[10]>

Enter the maximum number of messages per connection.
[10]>

Enter the maximum number of recipients per message.
[50]>

Do you want to override the hostname in the SMTP banner? [N]>

Would you like to specify a custom SMTP acceptance response? [N]>

Would you like to specify a custom SMTP rejection response? [N]>

Do you want to enable rate limiting per host? [N]>

Do you want to enable rate limiting per envelope sender? [N]>

Do you want to enable Directory Harvest Attack Prevention per host? [Y]>

Enter the maximum number of invalid recipients per hour from a remote host.
[25]>

Select an action to apply when a recipient is rejected due to DHAP:
1. Drop
2. Code
[1]>

Would you like to specify a custom SMTP DHAP response? [Y]>

Enter the SMTP code to use in the response. 550 is the standard code.
[550]>

Enter your custom SMTP response. Press Enter on a blank line to finish.

Would you like to use SenderBase for flow control by default? [Y]>

Would you like to enable anti-spam scanning? [Y]>

Would you like to enable anti-virus scanning? [Y]>

Do you want to allow encrypted TLS connections?
1. No
2. Preferred
3. Required
4. Preferred - Verify
5. Required - Verify
[1]>

Would you like to enable DKIM/DomainKeys signing? [N]>

Would you like to enable DKIM verification? [N]>

Would you like to change SPF/SIDF settings? [N]>

Would you like to enable DMARC verification? [N]>

Would you like to enable envelope sender verification? [N]>

Would you like to enable use of the domain exception table? [N]>

Do you wish to accept untagged bounces? [N]>

如果做任何更新或更改,请回到主CLI提示符并且确认所有更改。

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Document ID: 118496