many thanks to Jonathan Phillibert from Amazon Web Services
for investigating and reporting that responding to such packets
might lead to traffic amplification
Interface grouping is available on FreeBSD and OpenBSD. This will allow
you to enumerate only SoftEther virtual interfaces or exclude SoftEther
virtual interfaces, and be helpful when making custom scripts to start
DHCP client when virtual interface become up (=VPN connection
established) for example.
Usage examples as follows.
List all interfaces' names available on the system:
```
$ ifconfig -l
vtnet0 lo0 vpn_client0 vpn_client1 vpn_client2
```
Display a list of SoftEther virtual interfaces:
```
$ ifconfig -g softether
vpn_client0
vpn_client1
vpn_client2
```
Display details about SoftEther virtual interfaces that are up:
```
$ ifconfig -a -u -g softether
vpn_client0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
description: SoftEther Virtual Network Adapter
options=80000<LINKSTATE>
ether 5e:71:fa:f8:91:4a
hwaddr 58:9c:fc:10:34:2a
groups: tap softether
media: Ethernet autoselect
status: active
nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
Opened by PID 1445
```
Display details about interfaces except for SoftEther virtual interfaces:
```
$ ifconfig -a -G softether
vtnet0: flags=8863<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
options=80028<VLAN_MTU,JUMBO_MTU,LINKSTATE>
ether 58:9c:fc:00:f0:23
inet6 fe80::5a9c:fcff:fe00:f023%vtnet0 prefixlen 64 scopeid 0x1
inet 192.168.96.7 netmask 0xffffff00 broadcast 192.168.96.255
media: Ethernet autoselect (10Gbase-T <full-duplex>)
status: active
nd6 options=23<PERFORMNUD,ACCEPT_RTADV,AUTO_LINKLOCAL>
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
options=680003<RXCSUM,TXCSUM,LINKSTATE,RXCSUM_IPV6,TXCSUM_IPV6>
inet6 ::1 prefixlen 128
inet6 fe80::1%lo0 prefixlen 64 scopeid 0x2
inet 127.0.0.1 netmask 0xff000000
groups: lo
nd6 options=23<PERFORMNUD,ACCEPT_RTADV,AUTO_LINKLOCAL>
```
In contrast to Linux, FreeBSD's tap devices are still plumbed after fd
closed. The tap device must be destroyed in addition to closing fd
to delete virtual network interfaces used for VPN connection.
NicDelete command now works properly and virtual network interfaces used
by vpnclient are cleaned up when shutting down vpnclient.
=================================================================
==1505093==ERROR: AddressSanitizer: heap-use-after-free on address 0x607000366b88 at pc 0x7f72afadc34a bp 0x7f72990fa390 sp 0x7f72990fa388
READ of size 4 at 0x607000366b88 thread T22
#0 0x7f72afadc349 in GetCaps /home/ilia/SoftEtherVPN/src/Cedar/Server.c:1861
#1 0x7f72afadc382 in GetCapsInt /home/ilia/SoftEtherVPN/src/Cedar/Server.c:1802
#2 0x7f72afaf72a5 in GetServerCapsInt /home/ilia/SoftEtherVPN/src/Cedar/Server.c:1098
#3 0x7f72afaf7318 in GetServerCapsBool /home/ilia/SoftEtherVPN/src/Cedar/Server.c:1104
#4 0x7f72afaf771e in SiWriteHubCfg /home/ilia/SoftEtherVPN/src/Cedar/Server.c:4887
#5 0x7f72afaf771e in SiWriteHubCfg /home/ilia/SoftEtherVPN/src/Cedar/Server.c:4824
#6 0x7f72afaf7c0b in SiWriteHubs /home/ilia/SoftEtherVPN/src/Cedar/Server.c:5548
#7 0x7f72afaf7c0b in SiWriteHubs /home/ilia/SoftEtherVPN/src/Cedar/Server.c:5515
#8 0x7f72afaf81d6 in SiWriteConfigurationToCfg /home/ilia/SoftEtherVPN/src/Cedar/Server.c:3166
#9 0x7f72afaf86bc in SiWriteConfigurationFile /home/ilia/SoftEtherVPN/src/Cedar/Server.c:6593
#10 0x7f72afaf86bc in SiWriteConfigurationFile /home/ilia/SoftEtherVPN/src/Cedar/Server.c:6569
#11 0x7f72afaf8914 in SiSaverThread /home/ilia/SoftEtherVPN/src/Cedar/Server.c:6561
#12 0x7f72afaf8914 in SiSaverThread /home/ilia/SoftEtherVPN/src/Cedar/Server.c:6547
#13 0x7f72af6e0cfa in ThreadPoolProc /home/ilia/SoftEtherVPN/src/Mayaqua/Kernel.c:872
#14 0x7f72af6e0cfa in ThreadPoolProc /home/ilia/SoftEtherVPN/src/Mayaqua/Kernel.c:827
#15 0x7f72af76eeb4 in UnixDefaultThreadProc /home/ilia/SoftEtherVPN/src/Mayaqua/Unix.c:1604
#16 0x7f72af4ffc56 in start_thread (/lib64/libc.so.6+0x8cc56) (BuildId: 6107835fa7d4725691b2b7f6aaee7abe09f493b2)
#17 0x7f72af585a6f in __clone3 (/lib64/libc.so.6+0x112a6f) (BuildId: 6107835fa7d4725691b2b7f6aaee7abe09f493b2)
0x607000366b88 is located 24 bytes inside of 72-byte region [0x607000366b70,0x607000366bb8)
freed by thread T0 here:
#0 0x7f72afed7fc8 in __interceptor_free.part.0 (/lib64/libasan.so.8+0xd7fc8) (BuildId: 9501248886f79bf1482f3e153f794be742818172)
#1 0x7f72af76ed6f in UnixMemoryFree /home/ilia/SoftEtherVPN/src/Mayaqua/Unix.c:2072
previously allocated by thread T22 here:
#0 0x7f72afed92ff in malloc (/lib64/libasan.so.8+0xd92ff) (BuildId: 9501248886f79bf1482f3e153f794be742818172)
#1 0x7f72af76f35d in UnixMemoryAlloc /home/ilia/SoftEtherVPN/src/Mayaqua/Unix.c:2053
Thread T22 created by T0 here:
#0 0x7f72afe48966 in pthread_create (/lib64/libasan.so.8+0x48966) (BuildId: 9501248886f79bf1482f3e153f794be742818172)
#1 0x7f72af76f713 in UnixInitThread /home/ilia/SoftEtherVPN/src/Mayaqua/Unix.c:1683
SUMMARY: AddressSanitizer: heap-use-after-free /home/ilia/SoftEtherVPN/src/Cedar/Server.c:1861 in GetCaps
Shadow bytes around the buggy address:
0x607000366900: 00 00 00 fa fa fa fa fa 00 00 00 00 00 00 00 00
0x607000366980: 00 fa fa fa fa fa 00 00 00 00 00 00 00 00 00 fa
0x607000366a00: fa fa fa fa 00 00 00 00 00 00 00 00 00 fa fa fa
0x607000366a80: fa fa 00 00 00 00 00 00 00 00 00 fa fa fa fa fa
0x607000366b00: 00 00 00 00 00 00 00 00 00 fa fa fa fa fa fd fd
=>0x607000366b80: fd[fd]fd fd fd fd fd fa fa fa fa fa fd fd fd fd
0x607000366c00: fd fd fd fd fd fa fa fa fa fa fd fd fd fd fd fd
0x607000366c80: fd fd fd fa fa fa fa fa fd fd fd fd fd fd fd fd
0x607000366d00: fd fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x607000366d80: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x607000366e00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
specially crafted network packet lead to buffer overrun and process
crash. working exploit was provided by Cisco Talos team.
An integer underflow vulnerability exists in the vpnserver
OvsProcessData functionality of SoftEther VPN 5.01.9674 and 5.02. A
specially-crafted network packet can lead to denial of service. An
attacker can send a malicious packet to trigger this vulnerability.
The versions below were either tested or verified to be vulnerable by
Talos or confirmed to be vulnerable by the vendor.
SoftEther VPN 5.01.9674
SoftEther VPN 5.02
While 5.01.9674 is a development version, it is distributed at the time
of writing by Ubuntu and other Debian-based distributions.
