Tavis Ormandy discovered that the SSH daemon did not properly handle authentication packets with duplicated blocks. By sending specially crafted packets, a remote attacker could exploit this to cause the ssh daemon to drain all available CPU resources until the login grace time expired. (CVE-2006-4924)

Mark Dowd discovered a race condition in the server's signal handling.
A remote attacker could exploit this to crash the server.
(CVE-2006-5051).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

バナーによると、リモートホストにインストールされているバージョンの OpenSSH は、以下の複数の脆弱性の影響を受けています。

  - 競合状態が存在しており、これによって、承認されていないリモート攻撃者は、サービスをクラッシュするか、場合によってはポータブル OpenSSH 上で、影響を受けるホスト上のコードを実行できることがあります。悪用に成功するには、GSSAPI 認証が有効になっている必要があることに、注意してください。
    
  - 欠陥が存在しており、これによって攻撃者が、一部のプラットフォーム上のユーザー名の有効性を判断できることがあります。この問題では、GSSAPI 認証が有効になっている必要があることに注意してください。

  -  SSH バージョン 1 を使用する場合、サービスの可用性の喪失をもたらすことがある重複ブロックが含まれている SSH パケットを介して、問題がトリガされることがあります。

  -  Fedora Core 6 で（およびおそらくは他のシステムでも）、linux_audit_record_event() 関数での特定されていない脆弱性により、リモートの攻撃者が、監査ログに不適切な情報を注入できます。

リモートホストで実行されているバージョンの SunSSH に情報漏洩脆弱性があります。SSH の仕様の設計上の欠陥により、中間攻撃者が、標準構成の SSH 保護接続から最大 32 ビットまでの平文を回収できることがあります。攻撃者はこれを悪用して、機密情報にアクセスすることがあります。

このバージョンの SunSSH はいくつかのその他の問題の影響も受けやすくなっていますが、Nessus はそれらの問題をテストしていないことに、注意してください。

遠端主機上安裝的 SunSSH 版本有資訊洩漏弱點。SSH 規格的設計瑕疵允許攔截式攻擊者在標準組態中從 SSH 受保護的連線復原多達 32 位元的純文字。攻擊者可惡意利用此弱點來存取敏感資訊。

請注意，此版本的 SunSSH 也容易發生其他多個問題，但 Nessus 並未測試這些問題。

远程主机上运行的 SunSSH 版本存在信息泄露漏洞。SSH 规范中的设计缺陷可允许中间人攻击者从标准配置的受 SSH 保护的连接中恢复多达 32 位的明文。攻击者可利用这一点获取敏感信息的访问权限。

请注意，此 SunSSH 版本也易于发生多个其他问题，但 Nessus 未对其进行测试。

根据其标题，远程主机上安装的 OpenSSH 版本受到多种漏洞的影响：

  - 存在争用条件，可允许未经身份验证的远程攻击者使服务崩溃，或者在可移植 OpenSSH 上可能会在受影响的主机上执行代码。请注意，成功利用需要启用 GSSAPI 认证。
    
  - 存在可允许攻击者确定某些平台上的用户名有效性的缺陷。请注意，此问题需要启用 GSSAPI 认证。

  - 使用 SSH 版本 1 时，可通过包含重复块的 SSH 数据包来触发问题，可造成服务的可用性损失。

  - 在 Fedora Core 6（可能还有其他系统）上，linux_audit_record_event() 函数中不明的漏洞允许远程攻击者将错误信息注入清除日志。

It has been discovered that the signal handler implementing the login timeout in Debian's version of the OpenSSH server uses functions which are not async-signal-safe, leading to a denial of service vulnerability (CVE-2008-4109 ).

The problem was originally corrected in OpenSSH 4.4p1 (CVE-2006-5051 ), but the patch backported to the version released with etch was incorrect.

Systems affected by this issue suffer from lots of zombie sshd processes. Processes stuck with a '[net]' process title have also been observed. Over time, a sufficient number of processes may accumulate such that further login attempts are impossible. Presence of these processes does not indicate active exploitation of this vulnerability.
It is possible to trigger this denial of service condition by accident.

It was discovered that the ForceCommand directive could be bypassed.
If a local user created a malicious ~/.ssh/rc file, they could execute arbitrary commands as their user id. This only affected Ubuntu 7.10.
(CVE-2008-1657)

USN-355-1 fixed vulnerabilities in OpenSSH. It was discovered that the fixes for this issue were incomplete. A remote attacker could attempt multiple logins, filling all available connection slots, leading to a denial of service. This only affected Ubuntu 6.06 and 7.04.
(CVE-2008-4109).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

根據其標題，遠端主機上安裝的 OpenSSH 版本受多種弱點的影響：

  - 存在爭用條件，可能導致未經驗證的遠端攻擊者損毀服務，若是在可攜式 OpenSSH 中，可能還會在受影響的主機上執行任意程式碼。請注意，成功的惡意利用需要啟用 GSSAPI 驗證。
    
  - 存在可能導致攻擊者決定同一個平台上使用者名稱有效性的瑕疵。請注意，此問題需啟用 GSSAPI 驗證。

  - 使用 SSH 版本 1 時，內含重複區塊的 SSH 封包可導致服務不可用，藉此觸發問題。

  - 在 Fedora Core 6 (或其他系統) 上，linux_audit_record_event() 函數中的不明弱點導致遠端攻擊者將不正確的資訊放入稽核記錄。

Due to a faulty signal handler repeated login attempts could exhaust the maximum allowed connections and prevent further logins.
(CVE-2008-4109)

A problem where utmp entries where not deleted when users logged out was also fixed.

According to its banner, the version of OpenSSH installed on the remote host is affected by multiple vulnerabilities :

  - A race condition exists that may allow an     unauthenticated, remote attacker to crash the service     or, on portable OpenSSH, possibly execute code on the     affected host.  Note that successful exploitation     requires that GSSAPI authentication be enabled.
    
  - A flaw exists that may allow an attacker to determine     the validity of usernames on some platforms. Note that     this issue requires that GSSAPI authentication be     enabled.

  - When SSH version 1 is used, an issue can be triggered     via an SSH packet that contains duplicate blocks that     could result in a loss of availability for the service.

  - On Fedora Core 6 (and possibly other systems), an     unspecified vulnerability in the     linux_audit_record_event() function allows remote     attackers to inject incorrect information into     audit logs.

Due to a faulty signal handler repeated login attempts could exhaust the maximum allowed connections and prevent further logins.
(CVE-2008-4109)

The version of SunSSH running on the remote host has an information disclosure vulnerability.  A design flaw in the SSH specification could allow a man-in-the-middle attacker to recover up to 32 bits of plaintext from an SSH-protected connection in the standard configuration.  An attacker could exploit this to gain access to sensitive information.

Note that this version of SunSSH is also prone to several additional issues but Nessus did not test for them.

Tavis Ormandy of the Google Security Team discovered a Denial of Service vulnerability in the SSH protocol version 1 CRC compensation attack detector. This could allow a remote unauthenticated attacker to trigger excessive CPU utilization by sending a specially crafted SSH message, which would then deny ssh services to other users or processes (CVE-2006-4924, CVE-2006-4925). Please note that Mandriva ships with only SSH protocol version 2 enabled by default.

Next, an unsafe signal handler was found by Mark Dowd. This signal handler was vulnerable to a race condition that could be exploited to perform a pre-authentication DoS, and theoretically a pre-authentication remote code execution in the case where some authentication methods like GSSAPI are enabled (CVE-2006-5051).

Updated packages have been patched to correct this issue.

The version of OpenSSH running on the remote host is prior to version 4.4. Such versions are affected by multiple vulnerabilities:

 - A race condition exists that may allow an unauthenticated, remote attacker to crash the service or, on portable OpenSSH, possibly execute code on the affected host. Note that successful exploitation requires that GSSAPI authentication be enabled.
 - A flaw exists that may allow an attacker to determine the validity of usernames on some platforms. Note that this issue requires that GSSAPI authentication be enabled.
 - When SSH version 1 is used, an issue can be triggered via an SSH packet that contains duplicate blocks that could result in a loss of availability for the service.
 - On Fedora Core 6 (and possibly other systems), an unspecified vulnerability in the linux_audit_record_event() function allows remote attackers to inject incorrect information into audit logs.

ID	名前	製品	ファミリー	公開日	更新日	深刻度
27935	Ubuntu 5.04 / 5.10 / 6.06 LTS : openssh vulnerabilities (USN-355-1)	Nessus	Ubuntu Local Security Checks	2007/11/10	2021/1/19	high
22466	OpenSSH < 4.4 の複数の脆弱性	Nessus	Misc.	2006/9/28	2024/3/27	high
55992	SunSSH < 1.1.1 / 1.3 CBC の平文での漏洩	Nessus	Misc.	2011/8/29	2020/9/21	critical
55992	SunSSH < 1.1.1 / 1.3 CBC 純文字洩漏	Nessus	Misc.	2011/8/29	2020/9/21	critical
55992	SunSSH < 1.1.1 / 1.3 CBC 明文泄露	Nessus	Misc.	2011/8/29	2020/9/21	critical
22466	OpenSSH < 4.4 多种漏洞	Nessus	Misc.	2006/9/28	2024/3/27	high
34223	Debian DSA-1638-1 : openssh - denial of service	Nessus	Debian Local Security Checks	2008/9/17	2021/1/4	high
36855	Ubuntu 6.06 LTS / 7.04 / 7.10 : openssh vulnerabilities (USN-649-1)	Nessus	Ubuntu Local Security Checks	2009/4/23	2021/1/19	high
22466	OpenSSH < 4.4 多種弱點	Nessus	Misc.	2006/9/28	2024/3/27	high
34321	SuSE 10 Security Update : OpenSSH (ZYPP Patch Number 5627)	Nessus	SuSE Local Security Checks	2008/10/1	2021/1/14	medium
22466	OpenSSH < 4.4 Multiple Vulnerabilities	Nessus	Misc.	2006/9/28	2024/3/27	high
41244	SuSE9 Security Update : OpenSSH (YOU Patch Number 12257)	Nessus	SuSE Local Security Checks	2009/9/24	2021/1/14	medium
55992	SunSSH < 1.1.1 / 1.3 CBC Plaintext Disclosure	Nessus	Misc.	2011/8/29	2020/9/21	critical
24565	Mandrake Linux Security Advisory : openssh (MDKSA-2006:179)	Nessus	Mandriva Local Security Checks	2007/2/18	2021/1/6	high
3751	OpenSSH < 4.4 Multiple Vulnerabilities	Nessus Network Monitor	SSH	2006/9/28	2019/8/21	low

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