发布时间 :2002-08-12 00:00:00
修订时间 :2008-09-05 16:28:13

[原文]PF in OpenBSD 3.0 with the return-rst rule sets the TTL to 128 in the RST packet, which allows remote attackers to determine if a port is being filtered because the TTL is different than the default TTL.



- CVSS (基础分值)

CVSS分值: 5 [中等(MEDIUM)]
机密性影响: PARTIAL [很可能造成信息泄露]
完整性影响: NONE [不会对系统完整性产生影响]
可用性影响: NONE [对系统可用性无影响]
攻击复杂度: LOW [漏洞利用没有访问限制 ]
攻击向量: [--]
身份认证: NONE [漏洞利用无需身份认证]

- CPE (受影响的平台与产品)


- OVAL (用于检测的技术细节)


- 官方数据库链接
(官方数据源) MITRE
(官方数据源) NVD
(官方数据源) CNNVD

- 其它链接及资源
(VENDOR_ADVISORY)  BUGTRAQ  20020331 packet filter fingerprinting(open but closed, closed but filtered)
(VENDOR_ADVISORY)  XF  firewall-rst-fingerprint(8738)

- 漏洞信息

中危 设计错误
2002-08-12 00:00:00 2005-10-20 00:00:00

- 公告与补丁


- 漏洞信息

OpenBSD PF return-rst Rule Port Filtering Disclosure
Remote / Network Access Misconfiguration
Loss of Confidentiality
Exploit Unknown

- 漏洞描述

OpenBSD contains a flaw that may lead to an unauthorized information disclosure. The issue is triggered when a malicious user attempts to connect to a TCP port, which will disclose a RST response with a TTL value different from the default TTL value if a port is filtered resulting in a loss of confidentiality.

- 时间线

2002-03-31 Unknow
Unknow Unknow

- 解决方案

Currently, there are no known upgrades, patches, or workarounds available to correct this issue.

- 相关参考

- 漏洞作者

- 漏洞信息

OpenBSD PF TTL Fingerprinting Vulnerability
Design Error 4401
Yes No
2002-03-31 12:00:00 2009-07-11 11:56:00
This vulnerability discovery credited to Meder Kydyraliev <>.

- 受影响的程序版本

OpenBSD OpenBSD 3.0

- 漏洞讨论

PF is a packet filter implementation, available for OpenBSD. It is developed and maintained by the OpenBSD Project.

Under some circumstances, PF sends responses that can allow an attacker to gain information about the firewall ruleset. When an attempt is made to connect to a system via TCP on a port that is filtered by PF, and PF returns a RST, it is possible to differentiate between filtered and unfiltered ports. A port that is filtered will return a RST with a TTL field set to 128, whereas the operating system returns a value of 64 by default.

- 漏洞利用

This vulnerability may be exploited by using one of numerous available portscanning utilities and packet analysis utilities.

- 解决方案

Currently the SecurityFocus staff are not aware of any vendor-supplied patches for this issue. If you feel we are in error or are aware of more recent information, please mail us at: <>.

- 相关参考