安全机制概述
信息安全防护的目标
- 保密性 Confidentiality
- 完整性 Integrity
- 可用性 Usability
- 可控制性Controlability
- 不可否认性 Non-repudiation
安全防护环节
- 物理安全：各种设备/主机、机房环境
- 系统安全：主机或设备的操作系统
- 应用安全：各种网络服务、应用程序
- 网络安全：对网络访问的控制、防火墙规则
- 数据安全：信息的备份与恢复、加密解密
- 管理安全：各种保障性的规范、流程、方法安全
安全攻击： STRIDE
- Spoofing 假冒
- Tampering 篡改
- Repudiation 否认
- Information Disclosure 信息泄漏
- Denial of Service 拒绝服务
- Elevation of Privilege 提升权限
5安全设计基本原则
- 使用成熟的安全系统
- 以小人之心度输入数据
- 外部系统是不安全的
- 最小授权
- 减少外部接口
- 缺省使用安全模式
- 安全不是似是而非
- 从STRIDE思考
- 在入口处检查
- 从管理上保护好你的系统
安全算法
常用安全技术- 认证
- 授权
- 审计
- 安全通信
- 对称加密
- 公钥加密
- 单向加密
- 认证协议
- 密码/数据嗅探
- 数据操作
- 验证操作
- 相当于邮寄明信片
- telnet、FTP、POP3等等；不安全密码
- http、smtp、NFS等等；不安全信息
- Ldap、NIS、rsh等等；不安全验证
对称加密算法
对称加密：加密和解密使用同一个密钥 DES：Data Encryption Standard，56bits 3DES： AES：Advanced (128, 192, 256bits) Blowfish，Twofish IDEA，RC6，CAST5 特性：- 加密、解密使用同一个密钥，效率高
- 将原始数据分割成固定大小的块，逐个进行加密
- 密钥过多
- 密钥分发
- 数据来源无法确认10
非对称加密算法
公钥加密：密钥是成对出现 公钥：公开给所有人；public key 私钥：自己留存，必须保证其私密性；secret key 特点：- 用公钥加密数据，只能使用与之配对的私钥解密；反之亦然
- 数字签名：主要在于让接收方确认发送方身份
- 对称密钥交换：发送方用对方的公钥加密一个对称密钥后发送给对方
- 数据加密：适合加密较小数据
- 密钥长，加密解密效率低下
- RSA（加密，数字签名）,DSA（数字签名）,ELGamal
非对称加密
基于一对公钥/密钥对 用密钥对中的一个加密，另一个解密 实现加密： 接收者- 生成公钥/密钥对：P和S
- 公开公钥P，保密密钥S
- 使用接收者的公钥来加密消息M
- 将P(M)发送给接收者
- 使用密钥S来解密：M=S(P(M))
- 生成公钥/密钥对：P和S
- 公开公钥P，保密密钥S
- 使用密钥S来加密消息M
- 发送给接收者S(M)
- 使用发送者的公钥来解密M=P(S(M))
- 结合签名和加密
- 分离签名
CA和证书
PKI: Public Key Infrastructure
- 签证机构：CA（Certificate Authority）
- 注册机构：RA
- 证书吊销列表：CRL
- 证书存取库
X.509：定义了证书的结构以及认证协议标准
- 版本号
- 序列号
- 签名算法
- 颁发者
- 有效期限
- 主体名称
- 主体公钥
- CRL分发点
- 扩展信息
- 发行者签名
证书获取
证书类型：
- 证书授权机构的证书
- 服务器
- 用户证书
- 使用证书授权机构
- 生成签名请求（csr）
- 将csr发送给CA
- 从CA处接收签名
- 自已签发自己的公钥
安全协议
- SSL: Secure Socket Layer
- TLS: Transport Layer Security
-
- 1995：SSL 2.0 Netscape
- 1996: SSL 3.0
- 1999: TLS 1.0
- 2006: TLS 1.1 IETF(Internet工程任务组) RFC 4346
- 2008：TLS 1.2 当前使用
- 2015: TLS 1.3
- 机密性，认证，完整性，重放保护
- 握手阶段(协商阶段):客户端和服务器端认证对方身份（依赖于PKI体系，利用数字证书进行身份认证），并协商通信中使用的安全参数、密码套件以及主密钥。后续通信使用的所有密钥都是通过MasterSecret生成。
- 应用阶段:在握手阶段完成后进入，在应用阶段通信双方使用握手阶段协商好的密钥进行安全通信
SSL/TLS
- Handshake协议：包括协商安全参数和密码套件、服务器身份认证（客户端身份认证可选）、密钥交换
- ChangeCipherSpec 协议：一条消息表明握手协议已经完成
- Alert 协议：对握手协议中一些异常的错误提醒，分为fatal和warning两个级别，fatal类型错误会直接中断SSL链接，而warning级别的错误SSL链接仍可继续，只是会给出错误警告
- Record 协议：包括对消息的分段、压缩、消息认证和完整性保护、加密等
- HTTPS 协议：就是“HTTP 协议”和“SSL/TLS 协议”的组合。HTTP over SSL”或“HTTP over TLS”，对http协议的文本数据进行加密处理后，成为二进制形式传输
OpenSSL
OpenSSL：开源项目 三个组件：- openssl: 多用途的命令行工具，包openssl
- libcrypto: 加密算法库，包openssl-libs
- libssl：加密模块应用库，实现了ssl及tls，包nss
SSH
ssh: secure shell, protocol, 22/tcp, 安全的远程登录 具体的软件实现：- OpenSSH: ssh协议的开源实现，CentOS默认安装
- dropbear：另一个开源实现
- v1: 基于CRC-32做MAC，不安全；man-in-middle
- v2：双方主机协议选择安全的MAC方式
- 基于DH算法做密钥交换，基于RSA或DSA实现身份认证
- 基于password
- 基于key
openssl命令：
两种运行模式：交互模式和批处理模式 openssl version：程序版本号 标准命令、消息摘要命令、加密命令 标准命令：enc, ca, req, ...对称加密：
工具：openssl enc, gpg 算法：3des, aes, blowfish, twofish enc命令： 帮助： man enc 加密： openssl enc -e -des3 -a -salt -in testfile -out test.cipher解密： openssl enc -d -des3 -a -salt –in test.cipher -out testfile
单向加密
工具：md5sum, sha1sum, sha224sum,sha256sum…openssl dgst dgst命令： 帮助： man dgstopenssl dgst -md5 [-hex默认] /PATH/SOMEFILE openssl dgst -md5 testfile md5sum /PATH/TO/SOMEFILEMAC: Message Authentication Code，单向加密的一种延伸应用，用于实现网络通信中保证所传输数据的完整性机制CBC-MAC HMAC：使用md5或sha1算法31
生成用户密码
passwd命令: 帮助： man sslpasswdopenssl passwd -1 -salt SALT(最多8位) openssl passwd -1 –salt centos
生成随机数
帮助： man sslrandopenssl rand -base64|-hex NUM
NUM: 表示字节数；-hex时，每个字符为十六进制，相当于4位二进制，出现的字符数为NUM*232
生成密钥对
公钥加密 算法：RSA, ELGamal 工具：gpg, openssl rsautl（man rsautl） 数字签名： 算法：RSA, DSA, ELGamal 密钥交换： 算法：dh DSA: Digital Signature Algorithm DSS：Digital Signature Standard RSA：33 生成私钥openssl genrsa -out /PATH/TO/PRIVATEKEY.FILE NUM_BITS (umask 077; openssl genrsa –out test.key –des 2048) openssl rsa -in test.key –out test2.key 将加密key解密从私钥中提取出公钥
openssl rsa -in PRIVATEKEYFILE –pubout –out PUBLICKEYFILE Openssl rsa –in test.key –pubout –out test.key.pub
OpenSSL证书服务器搭建
PKI：Public Key Infrastructure
- CA
- RA
- CRL
- 证书存取库
证书申请及签署步骤：
- 生成申请请求
- RA核验
- CA签署
- 获取证书35
创建CA
openssl的配置文件： /etc/pki/tls/openssl.cnfHOME = .
oid_section = new_oids
openssl_conf = default_modules
[ default_modules ]
ssl_conf = ssl_module
[ ssl_module ]
system_default = crypto_policy
[ crypto_policy ]
.include /etc/crypto-policies/back-ends/opensslcnf.config
[ new_oids ]
tsa_policy1 = 1.2.3.4.1
tsa_policy2 = 1.2.3.4.5.6
tsa_policy3 = 1.2.3.4.5.7
[ ca ] # 语句块
default_ca = CA_default # The default ca section
[ CA_default ] # 语句块
dir = /etc/pki/CA # ca 相关的具体路径 证书
certs = $dir/certs # 存放证书的目录
crl_dir = $dir/crl # 证书兑换列表
database = $dir/index.txt # 数据库 存放所有证书的信息 自动更新
# several certs with same subject.
new_certs_dir = $dir/newcerts #新证书存放的路径
certificate = $dir/cacert.pem # The CA certificate
serial = $dir/serial # 编号 存放下一个要颁发的编号
crlnumber = $dir/crlnumber # 吊销列表的标号
# must be commented out to leave a V1 CRL
crl = $dir/crl.pem # 证书吊销列表文件名
private_key = $dir/private/cakey.pem# 私钥文件
x509_extensions = usr_cert # The extensions to add to the cert
name_opt = ca_default # Subject Name options
cert_opt = ca_default # Certificate field options
default_days = 365 # 默认有效期
default_crl_days= 30 # 30天发布一次私钥信息
default_md = sha256 # 默认加密算法
preserve = no #
policy = policy_match # 策略匹配
[ policy_match ]
countryName = match # 必须有的信息 国家
stateOrProvinceName = match # 省市
organizationName = match # 公司
organizationalUnitName = optional
commonName = supplied # 通用名 域名
emailAddress = optional #
[ policy_anything ] # 策略可以不一样
countryName = optional
stateOrProvinceName = optional
localityName = optional
organizationName = optional
organizationalUnitName = optional
commonName = supplied
emailAddress = optional
[ req ]
default_bits = 2048
default_md = sha256
default_keyfile = privkey.pem
distinguished_name = req_distinguished_name
attributes = req_attributes
x509_extensions = v3_ca # The extensions to add to the self signed cert
string_mask = utf8only
[ req_distinguished_name ]
countryName = Country Name (2 letter code)
countryName_default = XX
countryName_min = 2
countryName_max = 2
stateOrProvinceName = State or Province Name (full name)
localityName = Locality Name (eg, city)
localityName_default = Default City
0.organizationName = Organization Name (eg, company)
0.organizationName_default = Default Company Ltd
organizationalUnitName = Organizational Unit Name (eg, section)
commonName = Common Name (eg, your name or your server\'s hostname)
commonName_max = 64
emailAddress = Email Address
emailAddress_max = 64
[ req_attributes ]
challengePassword = A challenge password
challengePassword_min = 4
challengePassword_max = 20
unstructuredName = An optional company name
[ usr_cert ]
basicConstraints=CA:FALSE
nsComment = "OpenSSL Generated Certificate"
subjectKeyIdentifier=hash
authorityKeyIdentifier=keyid,issuer
[ v3_req ]
basicConstraints = CA:FALSE
keyUsage = nonRepudiation, digitalSignature, keyEncipherment
[ v3_ca ]
subjectKeyIdentifier=hash
authorityKeyIdentifier=keyid:always,issuer
basicConstraints = critical,CA:true
[ crl_ext ]
authorityKeyIdentifier=keyid:always
[ proxy_cert_ext ]
basicConstraints=CA:FALSE
nsComment = "OpenSSL Generated Certificate"
subjectKeyIdentifier=hash
authorityKeyIdentifier=keyid,issuer
proxyCertInfo=critical,language:id-ppl-anyLanguage,pathlen:3,policy:foo
[ tsa ]
default_tsa = tsa_config1 # the default TSA section
[ tsa_config1 ]
dir = /etc/pki/CA # TSA root directory
serial = $dir/tsaserial # The current serial number (mandatory)
crypto_device = builtin # OpenSSL engine to use for signing
signer_cert = $dir/tsacert.pem # The TSA signing certificate
# (optional)
certs = $dir/cacert.pem # Certificate chain to include in reply
# (optional)
signer_key = $dir/private/tsakey.pem # The TSA private key (optional)
signer_digest = sha256 # Signing digest to use. (Optional)
default_policy = tsa_policy1 # Policy if request did not specify it
# (optional)
other_policies = tsa_policy2, tsa_policy3 # acceptable policies (optional)
digests = sha1, sha256, sha384, sha512 # Acceptable message digests (mandatory)
accuracy = secs:1, millisecs:500, microsecs:100 # (optional)
clock_precision_digits = 0 # number of digits after dot. (optional)
ordering = yes # Is ordering defined for timestamps?
# (optional, default: no)
tsa_name = yes # Must the TSA name be included in the reply?
# (optional, default: no)
ess_cert_id_chain = no # Must the ESS cert id chain be included?
# (optional, default: no)
ess_cert_id_alg = sha1 # algorithm to compute certificate
# identifier (optional, default: sha1)
主配置文件(不需要修改)
创建所需要的文件
mkdir /etc/pki/CA/
mkdir /etc/pki/CA/{certs,crl,newcerts,private}
[root@djcy-200 CA]# tree
.
├── certs
├── crl
├── newcerts
└── private
mkdir /etc/pki/CA/crlnumber
touch /etc/pki/CA/index.txt 生成证书索引数据库文件
echo 01 > /etc/pki/CA/serial 指定第一个颁发证书的序列号
CA生成私钥
# 输入密码 每次签发证书都需认证
[root@djcy-200 CA]# (umask 066; openssl genrsa -out private/cakey.pem -des3 2048)
Generating RSA private key, 2048 bit long modulus (2 primes)
...................................+++++
..................................+++++
e is 65537 (0x010001)
Enter pass phrase for private/cakey.pem:
Verifying - Enter pass phrase for private/cakey.pem:
[root@djcy-200 CA]# tree
.
├── certs
├── crl
├── newcerts
└── private
└── cakey.pem
CA自签证书
参数说明:
-new: 生成新证书签署请求
-x509: 专用于CA生成自签证书
-key: 生成请求时用到的私钥文件
-days n：证书的有效期限
-out /PATH/TO/SOMECERTFILE: 证书的保存路径
[root@djcy-200 CA]# openssl req -new -x509 -key private/cakey.pem -days 18250 -out /etc/pki/CA/cacert.pem
Enter pass phrase for private/cakey.pem:
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [XX]:CN
State or Province Name (full name) []:BeiJing
Locality Name (eg, city) [Default City]:BeiJing
Organization Name (eg, company) [Default Company Ltd]:devops
Organizational Unit Name (eg, section) []:ops
Common Name (eg, your name or your server's hostname) []:ca.devops.com
Email Address []:admin@devops.com
[root@djcy-200 CA]# tree
.
├── cacert.pem
├── certs
├── crl
├── newcerts
└── private
└── cakey.pem
4 directories, 2 files查看
查看证书信息
[root@djcy-200 CA]# openssl x509 -in cacert.pem -noout -text
Certificate:
Data:
Version: 3 (0x2)
Serial Number:
11:10:a5:ca:51:77:cb:43:06:61:42:27:9d:ec:5e:35:d7:9b:61:17
Signature Algorithm: sha256WithRSAEncryption
Issuer: C = CN, ST = BeiJing, L = BeiJing, O = devops, OU = ops, CN = ca.devops.com, emailAddress = admin@devops.com
Validity
Not Before: Aug 2 13:34:53 2020 GMT
Not After : Jul 21 13:34:53 2070 GMT
Subject: C = CN, ST = BeiJing, L = BeiJing, O = devops, OU = ops, CN = ca.devops.com, emailAddress = admin@devops.com
'''''''' 省略
# 只查看某些内容
[root@djcy-200 CA]# openssl x509 -in cacert.pem -noout -dates
notBefore=Aug 2 13:34:53 2020 GMT
notAfter=Jul 21 13:34:53 2070 GMT
客户端请求颁发证书
生成私钥
[root@djcy-62 ~]# mkdir ca [root@djcy-62 ~]# cd ca/ [root@djcy-62 ca]# (umask 066;openssl genrsa -out app.key 1024) Generating RSA private key, 1024 bit long modulus (2 primes) ............+++++ ......................+++++ e is 65537 (0x010001) [root@djcy-62 ca]# ll total 4 -rw------- 1 root root 891 Aug 2 21:43 app.key
使用私钥生成请求
[root@djcy-62 ca]# openssl req -new -key app.key -out app.csr You are about to be asked to enter information that will be incorporated into your certificate request. What you are about to enter is what is called a Distinguished Name or a DN. There are quite a few fields but you can leave some blank For some fields there will be a default value, If you enter '.', the field will be left blank. ----- Country Name (2 letter code) [XX]:CN # 必须跟CA服务器一致 State or Province Name (full name) []:BeiJing # 必须跟CA服务器一致 Locality Name (eg, city) [Default City]:ChaoYang Organization Name (eg, company) [Default Company Ltd]:devops # 必须跟CA服务器一致 Organizational Unit Name (eg, section) []:webdev Common Name (eg, your name or your server's hostname) []:www.devops.com # 颁发的域名 Email Address []:dev@devops.com Please enter the following 'extra' attributes to be sent with your certificate request A challenge password []: An optional company name []: [root@djcy-62 ca]# ll total 8 -rw-r--r-- 1 root root 700 Aug 2 21:47 app.csr -rw------- 1 root root 891 Aug 2 21:43 app.key
发送请求秘钥到CA服务器
[root@djcy-62 ca]# scp app.csr bjcy-200.host.io:/etc/pki/CA/
查看服务器颁发的密码
[root@djcy-62 ca]# openssl x509 -in app.crt -noout -text
Certificate:
Data:
Version: 3 (0x2)
Serial Number: 1 (0x1)
Signature Algorithm: sha256WithRSAEncryption
Issuer: C = CN, ST = BeiJing, L = BeiJing, O = devops, OU = ops, CN = ca.devops.com, emailAddress = admin@devops.com
Validity
Not Before: Aug 2 14:01:05 2020 GMT
Not After : Jul 31 14:01:05 2030 GMT
Subject: C = CN, ST = BeiJing, O = devops, OU = webdev, CN = www.devops.com, emailAddress = dev@devops.com
Subject Public Key Info:
''''''' 省略'
CA授权客户端
[root@djcy-200 CA]# touch index.txt # 数据库文件存放着所有的申请授权信息
[root@djcy-200 CA]# echo 01 > /etc/pki/CA/serial # 开始申请的编号 每次都会增加
[root@djcy-200 CA]# openssl ca -in app.csr -out certs/app.crt -days 3650 # 开始授权
Using configuration from /etc/pki/tls/openssl.cnf
Enter pass phrase for /etc/pki/CA/private/cakey.pem:
Check that the request matches the signature
Signature ok
Certificate Details:
Serial Number: 1 (0x1)
Validity
Not Before: Aug 2 14:01:05 2020 GMT
Not After : Jul 31 14:01:05 2030 GMT
Subject:
countryName = CN
stateOrProvinceName = BeiJing
organizationName = devops
organizationalUnitName = webdev
commonName = www.devops.com
emailAddress = dev@devops.com
X509v3 extensions:
X509v3 Basic Constraints:
CA:FALSE
Netscape Comment:
OpenSSL Generated Certificate
X509v3 Subject Key Identifier:
BF:F7:D0:7A:0B:B8:11:6E:27:64:69:C2:7D:3D:38:62:69:E7:4A:10
X509v3 Authority Key Identifier:
keyid:31:BC:8B:B0:A6:F8:FF:B7:6E:F9:B2:E5:7C:80:B8:47:6C:AA:AB:1D
Certificate is to be certified until Jul 31 14:01:05 2030 GMT (3650 days)
Sign the certificate? [y/n]:y # 是否授权
1 out of 1 certificate requests certified, commit? [y/n]y # 确认
Write out database with 1 new entries
Data Base Updated
[root@djcy-200 CA]# tree
.
├── app.csr
├── cacert.pem
├── certs
│ └── app.crt # 生产的私钥文件
├── crl
├── index.txt
├── index.txt.attr
├── index.txt.old
├── newcerts
│ └── 01.pem # 和 certs下的 app.crt 是同一个文件
├── private
│ └── cakey.pem
├── serial
└── serial.old
4 directories, 10 files
[root@djcy-200 CA]# cat index.txt # 数据库文件
V 300731140105Z 01 unknown /C=CN/ST=BeiJing/O=devops/OU=webdev/CN=www.devops.com/emailAddress=dev@devops.com
[root@djcy-200 CA]# cat serial # 下次申请的编号
02
CA吊销证书
[root@djcy-200 CA]# echo 01 > /etc/pki/CA/crlnumber
[root@djcy-200 CA]# openssl ca -revoke newcerts/01.pem 指定吊销证书
Using configuration from /etc/pki/tls/openssl.cnf
Enter pass phrase for /etc/pki/CA/private/cakey.pem:
Revoking Certificate 01.
Data Base Updated
[root@djcy-200 CA]# tree
.
├── app.csr
├── cacert.pem
├── certs
│ └── app.crt
├── crl
├── crlnumber
├── index.txt
├── index.txt.attr
├── index.txt.attr.old
├── index.txt.old
├── newcerts
│ └── 01.pem
├── private
│ └── cakey.pem
├── serial
└── serial.old
4 directories, 12 files
[root@djcy-200 CA]# openssl ca -gencrl -out crl.pem # 生成证书吊销列表
Using configuration from /etc/pki/tls/openssl.cnf
Enter pass phrase for /etc/pki/CA/private/cakey.pem:
[root@djcy-200 CA]# tree
.
├── app.csr
├── cacert.pem
├── certs
│ └── app.crt
├── crl
├── crlnumber
├── crlnumber.old
├── crl.pem
├── index.txt
├── index.txt.attr
├── index.txt.attr.old
├── index.txt.old
├── newcerts
│ └── 01.pem
├── private
│ └── cakey.pem
├── serial
└── serial.old
4 directories, 14 files
[root@djcy-200 CA]# # 查看吊销列表文件
[root@djcy-200 CA]# openssl crl -in crl
crl/ crlnumber crlnumber.old crl.pem
[root@djcy-200 CA]# openssl crl -in crl.pem -noout -text
Certificate Revocation List (CRL):
Version 2 (0x1)
Signature Algorithm: sha256WithRSAEncryption
Issuer: C = CN, ST = BeiJing, L = BeiJing, O = devops, OU = ops, CN = ca.devops.com, emailAddress = admin@devops.com
Last Update: Aug 2 14:21:56 2020 GMT
Next Update: Sep 1 14:21:56 2020 GMT
CRL extensions:
X509v3 CRL Number:
1
Revoked Certificates:
Serial Number: 01
Revocation Date: Aug 2 14:20:37 2020 GMT
Signature Algorithm: sha256WithRSAEncryption
29:af:64:35:f5:aa:48:dd:7b:9d:0e:2c:a0:73:95:a1:e3:9a:
fc:16:a9:e0:51:7d:a8:ee:f1:c4:f1:83:f9:b3:88:f2:f5:12:
06:27:f7:f0:92:19:91:7b:f6:bc:30:ed:c6:34:ed:26:2d:ae:
a7:2b:a2:7f:c2:60:9b:e1:24:2d:23:34:7b:7c:5e:ee:66:07:
da:2f:c5:8e:35:e8:65:aa:89:da:d7:1f:df:53:9b:c6:4a:78:
a8:09:fe:f3:0d:f4:0d:d6:65:48:0b:3d:75:73:19:26:db:ba:
d0:0d:74:0c:c2:89:30:e5:33:f4:db:fd:73:e8:1e:07:30:1c:
05:03:47:df:b3:82:26:e7:73:64:14:07:b9:f3:70:eb:8d:c0:
fb:74:07:d8:22:ad:ce:3c:2e:ad:4a:00:cb:6c:9e:60:6c:dd:
8c:14:ea:95:69:4a:be:ab:57:25:2d:ed:54:5a:45:04:13:4c:
3a:90:23:96:d8:1b:01:c3:c6:a3:55:cf:8e:8b:c7:85:08:9b:
44:ab:e8:eb:0f:c5:7c:8d:05:ef:d8:db:45:2c:36:32:f9:0c:
56:db:6b:aa:72:1d:68:a8:4c:3f:7a:58:fc:26:cf:0c:53:d1:
d2:57:33:4a:22:44:89:49:74:7a:1b:4f:91:0d:0f:59:5d:b0:
83:28:66:02