BKDR_BAYROB.XCK

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It does not have any propagation routine.

As of this writing, the said sites are inaccessible.

Arrival Details

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This Trojan drops the following copies of itself into the affected system and executes them:

• %System Root%\uijuoja\dvw{random 5 characters}y4qjxddhly.exe - deleted afterwards
• %System Root%\uijuoja\ephdwiuepuu.exe
• %System Root%\uijuoja\flenvmby.exe

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It drops the following files:

• %Windows%\uijuoja\jeaxup (for Windows XP only) - deleted afterwards
• %System Root%\uijuoja\jeaxup
• %System Root%\uijuoja\eymssgkrjx
• %System Root%\uijuoja\nnqwqa

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It creates the following folders:

• %Windows%\uijuoja
• %System Root%\uijuoja

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It displays the following fake error messages:

Autostart Technique

This Trojan registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Office TP Auto-Discovery Adaptive
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Office TP Auto-Discovery Adaptive
ImagePath = "%System Root%\uijuoja\ephdwiuepuu.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Office TP Auto-Discovery Adaptive
DisplayName = "Office TP Auto-Discovery Adaptive"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Office TP Auto-Discovery Adaptive
ObjectName = "LocalSystem"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Office TP Auto-Discovery Adaptive
Type = "272"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Office TP Auto-Discovery Adaptive
ErrorControl = "0"

It adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Event Volume Shell Driver Hardware = "%System Root%\uijuoja\ephdwiuepuu.exe"

It registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Office TP Auto-Discovery Adaptive

Propagation

This Trojan does not have any propagation routine.

Download Routine

This Trojan accesses the following websites to download files:

• http://{hostname}.net/index.php

As of this writing, the said sites are inaccessible.

NOTES:

The variable {hostname} is generated through concatenating two strings from the following list:

• above
• action
• advance
• afraid
• against
• airplane
• almost
• alone
• already
• although
• always
• amount
• anger
• angry
• animal
• another
• answer
• appear
• apple
• around
• arrive
• article
• attempt
• banker
• basket
• battle
• beauty
• became
• because
• become
• before
• begin
• behind
• being
• believe
• belong
• beside
• better
• between
• beyond
• bicycle
• board
• borrow
• bottle
• bottom
• branch
• bread
• bridge
• bright
• bring
• broad
• broken
• brought
• brown
• building
• built
• business
• butter
• captain
• carry
• catch
• caught
• century
• chair
• chance
• character
• charge
• chief
• childhood
• children
• choose
• cigarette
• circle
• class
• clean
• clear
• close
• clothes
• college
• company
• complete
• condition
• consider
• contain
• continue
• control
• corner
• country
• course
• cover
• crowd
• daughter
• decide
• degree
• delight
• demand
• desire
• destroy
• device
• difference
• different
• difficult
• dinner
• direct
• discover
• distance
• distant
• divide
• doctor
• dollar
• double
• doubt
• dress
• dried
• during
• early
• eearly
• effort
• either
• electric
• electricity
• english
• enough
• enter
• escape
• evening
• every
• except
• expect
• experience
• explain
• family
• famous
• fancy
• father
• fellow
• fence
• fifteen
• fight
• figure
• finger
• finish
• flier
• flower
• follow
• foreign
• forest
• forever
• forget
• fortieth
• forward
• found
• fresh
• friend
• further
• future
• garden
• gather
• general
• gentle
• gentleman
• glass
• glossary
• goodbye
• govern
• guard
• happen
• health
• heard
• heart
• heaven
• heavy
• history
• honor
• however
• hunger
• husband
• include
• increase
• indeed
• industry
• inside
• instead
• journey
• kitchen
• known
• labor
• ladder
• language
• large
• laugh
• laughter
• leader
• leave
• length
• letter
• likely
• listen
• little
• machine
• manner
• market
• master
• material
• matter
• mayor
• measure
• meeting
• member
• method
• middle
• might
• million
• minute
• mister
• modern
• morning
• mother
• mountain
• movement
• nation
• nature
• nearly
• necessary
• needle
• neighbor
• neither
• niece
• night
• north
• nothing
• notice
• number
• object
• oclock
• office
• often
• opinion
• order
• orderly
• outside
• paint
• partial
• party
• people
• perfect
• perhaps
• period
• person
• picture
• pleasant
• please
• pleasure
• position
• possible
• power
• prepare
• present
• president
• pretty
• probable
• probably
• problem
• produce
• promise
• proud
• public
• quarter
• question
• quiet
• rather
• ready
• realize
• reason
• receive
• record
• remember
• report
• require
• result
• return
• ridden
• right
• river
• round
• safety
• school
• season
• separate
• service
• settle
• severa
• several
• shake
• share
• shore
• short
• should
• shoulder
• shout
• silver
• simple
• single
• sister
• smell
• smoke
• soldier
• space
• speak
• special
• spent
• spread
• spring
• square
• station
• still
• store
• storm
• straight
• strange
• stranger
• stream
• street
• strength
• strike
• strong
• student
• subject
• succeed
• success
• sudden
• suffer
• summer
• supply
• suppose
• surprise
• sweet
• system
• therefore
• thick
• think
• third
• those
• though
• thought
• through
• thrown
• together
• toward
• trade
• train
• training
• travel
• trouble
• trust
• twelve
• twenty
• understand
• understood
• until
• valley
• value
• various
• wagon
• water
• weather
• welcome
• wheat
• whether
• while
• white
• whose
• window
• winter
• within
• without
• woman
• women
• wonder
• worth
• would
• write
• written
• yellow

The backdoor component may connect to its own list of URLs to download a configuration file. This configuration file may contain the backdoor commands as well as the target applications and websites from where it steals information. Note that the contents of the file may change anytime depending on the C&C.

It does not have rootkit capabilities.

It does not exploit any vulnerability.