发现 NSS 未正确处理某些空 SSLv2 信息。远程攻击者可能利用此问题造成 NSS 崩溃，从而导致拒绝服务。

请注意，Tenable Network Security 已直接从 Ubuntu 安全公告中提取上述描述块。Tenable 已尝试在不引入其他问题的情况下，尽可能进行了自动清理和排版。

来自 Red Hat 安全公告 2017:1365： nss 更新现已可用于 Red Hat Enterprise Linux 7。 Red Hat 产品安全团队将此更新评级为具有重要安全影响。可从“参考”部分中的 CVE 链接获取通用漏洞评分系统 (CVSS) 基本分数，其针对每个漏洞给出了详细的严重性等级。 网络安全服务 (NSS) 是一组库，专用于支持启用了安全性的客户端和服务器应用程序的跨平台开发。 安全补丁： * 在 NSS 处理空 SSLv2 消息的方式中发现空指针取消引用缺陷。攻击者可利用此缺陷，导致针对 NSS 库编译的服务器应用程序崩溃。(CVE-2017-7502) 缺陷补丁： * 已更新网络安全服务 (NSS) 代码和证书授权 (CA) 列表，以符合最新 Mozilla Firefox Extended Support Release (ESR) 发布的建议。更新的 CA 列表可提高与在 Internet 公钥基础设施 (PKI) 中使用之证书的兼容性。为避免证书验证遭拒，Red Hat 建议于 2017 年 6 月 12 日安装更新的 CA 列表。(BZ# 1451421)

安全修复：- 在 NSS 处理空 SSLv2 消息的方式中发现空指针取消引用缺陷。攻击者可利用此缺陷，导致针对 NSS 库编译的服务器应用程序崩溃。(CVE-2017-7502) 缺陷修复：- 已更新网络安全服务 (NSS) 代码和认证机构 (CA) 列表，以符合最新 Mozilla Firefox Extended Support Release (ESR) 发布的建议。更新的 CA 列表可提高与在 Internet 公钥基础设施 (PKI) 中使用之证书的兼容性。为避免证书验证遭拒，考虑于 2017 年 6 月 12 日安装更新的 CA 列表。

Linux/Unix 主机中安装的一个或多个程序包受到一个漏洞影响，而供应商没有提供补丁程序。

  - 自 3.24.0 [] 以来，当服务器接收到空 SSLv2 消息时发现  ，从而导致远程攻击者造成拒绝服务，因此 NSS 中存在空指针取消引用漏洞。 (CVE-2017-7502)

请注意，Nessus 依赖供应商报告的程序包是否存在进行判断。

The remote NewStart CGSL host, running version MAIN 4.05, has nss packages installed that are affected by multiple vulnerabilities:

  - An out-of-bounds write flaw was found in the way NSS     performed certain Base64-decoding operations. An     attacker could use this flaw to create a specially     crafted certificate which, when parsed by NSS, could     cause it to crash or execute arbitrary code, using the     permissions of the user running an application compiled     against the NSS library. (CVE-2017-5461)

  - A null pointer dereference flaw was found in the way NSS     handled empty SSLv2 messages. An attacker could use this     flaw to crash a server application compiled against the     NSS library. (CVE-2017-7502)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Oracle Linux 6 host has packages installed that are affected by a vulnerability as referenced in the ELSA-2017-1364 advisory.

    [3.28.4-3.0.1]
    - Added nss-vendor.patch to change vendor
    - Temporarily disable some tests until expired PayPalEE.cert is renewed

    [3.28.4-3]
    - Fix zero-length record treatment for stream ciphers and SSLv2

    [3.28.4-2]
    - Include CKBI 2.14 and updated CA constraints from NSS 3.28.5

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 6 host has packages installed that are affected by a vulnerability as referenced in the RHSA-2017:1364 advisory.

    Network Security Services (NSS) is a set of libraries designed to support the cross-platform development     of security-enabled client and server applications.

    Security Fix(es):

    * A null pointer dereference flaw was found in the way NSS handled empty SSLv2 messages. An attacker could     use this flaw to crash a server application compiled against the NSS library. (CVE-2017-7502)

    Bug Fix(es):

    * The Network Security Services (NSS) code and Certificate Authority (CA) list have been updated to meet     the recommendations as published with the latest Mozilla Firefox Extended Support Release (ESR). The     updated CA list improves compatibility with the certificates that are used in the Internet Public Key     Infrastructure (PKI). To avoid certificate validation refusals, Red Hat recommends installing the updated     CA list on June 12, 2017. (BZ#1448488)

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Security Fix(es) :

  - A NULL pointer dereference flaw was found in the way NSS     handled empty SSLv2 messages. An attacker could use this     flaw to crash a server application compiled against the     NSS library. (CVE-2017-7502)

Bug Fix(es) :

  - The Network Security Services (NSS) code and Certificate     Authority (CA) list have been updated to meet the     recommendations as published with the latest Mozilla     Firefox Extended Support Release (ESR). The updated CA     list improves compatibility with the certificates that     are used in the Internet Public Key Infrastructure     (PKI). To avoid certificate validation refusals,     consider installing the updated CA list on June 12,     2017.

According to the version of the nss packages installed, the EulerOS installation on the remote host is affected by the following vulnerability :

  - A null pointer dereference flaw was found in the way     NSS handled empty SSLv2 messages. An attacker could use     this flaw to crash a server application compiled     against the NSS library. (CVE-2017-7502)

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

ID	名前	製品	ファミリー	公開日	更新日	深刻度
100988	Ubuntu 14.04 LTS / 16.04 LTS：NSS 漏洞 (USN-3336-1)	Nessus	Ubuntu Local Security Checks	2017/6/22	2024/8/27	high
100526	Oracle Linux 7 : nss (ELSA-2017-1365)	Nessus	Oracle Linux Local Security Checks	2017/5/31	2024/11/1	high
100536	Scientific Linux 安全更新：SL7.x x86_64 上的 nss	Nessus	Scientific Linux Local Security Checks	2017/5/31	2021/1/14	high
221690	Linux Distros 未修补的漏洞: CVE-2017-7502	Nessus	Misc.	2025/3/4	2025/3/4	high
127337	NewStart CGSL MAIN 4.05 : nss Multiple Vulnerabilities (NS-SA-2019-0105)	Nessus	NewStart CGSL Local Security Checks	2019/8/12	2021/1/14	critical
100525	Oracle Linux 6 : nss (ELSA-2017-1364)	Nessus	Oracle Linux Local Security Checks	2017/5/31	2024/10/22	high
100531	RHEL 6 : nss (RHSA-2017:1364)	Nessus	Red Hat Local Security Checks	2017/5/31	2024/11/4	high
100535	Scientific Linux Security Update : nss on SL6.x i386/x86_64 (20170530)	Nessus	Scientific Linux Local Security Checks	2017/5/31	2021/1/14	high
100701	EulerOS 2.0 SP1 : nss (EulerOS-SA-2017-1108)	Nessus	Huawei Local Security Checks	2017/6/9	2021/1/6	high

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