Tuesday, May 11, 2021

Mikrotik RouterOS 6.46.5 Memory Corruption / Assertion Failure

Advisory: four vulnerabilities found in MikroTik's RouterOS


Details
=======

Product: MikroTik's RouterOS
Vendor URL: https://mikrotik.com/
Vendor Status: no fix yet
CVE: CVE-2020-20214, CVE-2020-20222, CVE-2020-20236, CVE-2020-20237
Credit: Qian Chen(@cq674350529) of Qihoo 360 Nirvan Team


Product Description
==================

RouterOS is the operating system used on the MikroTik's devices, such as
switch, router and access point.


Description of vulnerabilities
==========================
These vulnerabilities were reported to the vendor almost one year ago. And
the vendor confirmed these vulnerabilities. However, there is still no fix
for them yet.
By the way, the three vulnerabilities in sniffer binary are different from
each one.

1. CVE-2020-20214
The btest process suffers from an assertion failure vulnerability. There is
a reachable assertion in the btest process. By sending a crafted packet, an
authenticated remote user can crash the btest process due to assertion
failure.

Against stable 6.46.5, the poc resulted in the following crash dump.

# cat /rw/logs/backtrace.log
2020.06.19-15:51:[email protected]:
2020.06.19-15:51:[email protected]:
2020.06.19-15:51:[email protected]: /nova/bin/btest
2020.06.19-15:51:[email protected]: --- signal=6
--------------------------------------------
2020.06.19-15:51:[email protected]:
2020.06.19-15:51:[email protected]: eip=0x7772255b eflags=0x00000246
2020.06.19-15:51:[email protected]: edi=0x00fe0001 esi=0x7772a200 ebp=0x7fdcf880
esp=0x7fdcf878
2020.06.19-15:51:[email protected]: eax=0x00000000 ebx=0x0000010f ecx=0x0000010f
edx=0x00000006
2020.06.19-15:51:[email protected]:
2020.06.19-15:51:[email protected]: maps:
2020.06.19-15:51:[email protected]: 08048000-08057000 r-xp 00000000 00:0c 1006
/nova/bin/btest
2020.06.19-15:51:[email protected]: 776f4000-77729000 r-xp 00000000 00:0c 964
/lib/libuClibc-0.9.33.2.so
2020.06.19-15:51:[email protected]: 7772d000-77747000 r-xp 00000000 00:0c 960
/lib/libgcc_s.so.1
2020.06.19-15:51:[email protected]: 77748000-77757000 r-xp 00000000 00:0c 944
/lib/libuc++.so
2020.06.19-15:51:[email protected]: 77758000-77775000 r-xp 00000000 00:0c 947
/lib/libucrypto.so
2020.06.19-15:51:[email protected]: 77776000-777c2000 r-xp 00000000 00:0c 946
/lib/libumsg.so
2020.06.19-15:51:[email protected]: 777c8000-777cf000 r-xp 00000000 00:0c 958
/lib/ld-uClibc-0.9.33.2.so
2020.06.19-15:51:[email protected]:
2020.06.19-15:51:[email protected]: stack: 0x7fdd0000 - 0x7fdcf878
2020.06.19-15:51:[email protected]: 00 a0 72 77 00 a0 72 77 b8 f8 dc 7f 77 e0 71
77 06 00 00 00 00 a2 72 77 20 00 00 00 00 00 00 00
2020.06.19-15:51:[email protected]: 16 00 00 00 18 f9 dc 7f b4 f8 dc 7f e4 2a 7c
77 01 00 00 00 e4 2a 7c 77 16 00 00 00 01 00 fe 00
2020.06.19-15:51:[email protected]:
2020.06.19-15:51:[email protected]: code: 0x7772255b
2020.06.19-15:51:[email protected]: 5b 3d 00 f0 ff ff 76 0e 8b 93 cc ff ff ff f7
d8

This vulnerability was initially found in long-term 6.44.5, and it seems
that the latest stable version 6.48.2 still suffers from this vulnerability.

2. CVE-2020-20222
The sniffer process suffers from a memory corruption vulnerability. By
sending a crafted packet, an authenticated remote user can crash the
sniffer process due to NULL pointer dereference.

Against stable 6.46.5, the poc resulted in the following crash dump.

# cat /rw/logs/backtrace.log
2020.06.19-16:36:[email protected]:
2020.06.19-16:36:[email protected]:
2020.06.19-16:36:[email protected]: /nova/bin/sniffer
2020.06.19-16:36:[email protected]: --- signal=11
--------------------------------------------
2020.06.19-16:36:[email protected]:
2020.06.19-16:36:[email protected]: eip=0x08050e33 eflags=0x00010206
2020.06.19-16:36:[email protected]: edi=0x08057a24 esi=0x7f85c094 ebp=0x7f85c0c8
esp=0x7f85c080
2020.06.19-16:36:[email protected]: eax=0x00000000 ebx=0x7f85c090 ecx=0x00ff0000
edx=0x08059678
2020.06.19-16:36:[email protected]:
2020.06.19-16:36:[email protected]: maps:
2020.06.19-16:36:[email protected]: 08048000-08056000 r-xp 00000000 00:0c 1034
/nova/bin/sniffer
2020.06.19-16:36:[email protected]: 776ce000-77703000 r-xp 00000000 00:0c 964
/lib/libuClibc-0.9.33.2.so
2020.06.19-16:36:[email protected]: 77707000-77721000 r-xp 00000000 00:0c 960
/lib/libgcc_s.so.1
2020.06.19-16:36:[email protected]: 77722000-77731000 r-xp 00000000 00:0c 944
/lib/libuc++.so
2020.06.19-16:36:[email protected]: 77732000-7773a000 r-xp 00000000 00:0c 950
/lib/libubox.so
2020.06.19-16:36:[email protected]: 7773b000-77787000 r-xp 00000000 00:0c 946
/lib/libumsg.so
2020.06.19-16:36:[email protected]: 7778d000-77794000 r-xp 00000000 00:0c 958
/lib/ld-uClibc-0.9.33.2.so
2020.06.19-16:36:[email protected]:
2020.06.19-16:36:[email protected]: stack: 0x7f85d000 - 0x7f85c080
2020.06.19-16:36:[email protected]: 2c 08 07 08 04 00 fe 08 fe 00 00 00 20 ad 05
08 00 0c 07 08 a0 0b 07 08 af 0b 07 08 04 7a 05 08
2020.06.19-16:36:[email protected]: 08 00 00 00 24 7a 05 08 ff 00 00 00 00 00 00
00 08 c2 85 7f e4 7a 78 77 d8 c0 85 7f e4 7a 78 77
2020.06.19-16:36:[email protected]:
2020.06.19-16:36:[email protected]: code: 0x8050e33
2020.06.19-16:36:[email protected]: 0b 48 0c 89 fa 89 d8 e8 7d f1 ff ff 50 50 53
56

This vulnerability was initially found in long-term 6.44.6, and it seems
that the latest stable version 6.48.2 still suffers from this vulnerability.

3. CVE-2020-20236
The sniffer process suffers from a memory corruption vulnerability. By
sending a crafted packet, an authenticated remote user can crash the
sniffer process due to invalid memory access.

Against stable 6.46.5, the poc resulted in the following crash dump.

# cat /rw/logs/backtrace.log
2020.06.19-16:58:[email protected]:
2020.06.19-16:58:[email protected]:
2020.06.19-16:58:[email protected]: /nova/bin/sniffer
2020.06.19-16:58:[email protected]: --- signal=11
--------------------------------------------
2020.06.19-16:58:[email protected]:
2020.06.19-16:58:[email protected]: eip=0x08050dac eflags=0x00010202
2020.06.19-16:58:[email protected]: edi=0x08057a24 esi=0x00000001 ebp=0x7f8df428
esp=0x7f8df3e0
2020.06.19-16:58:[email protected]: eax=0x08073714 ebx=0x08073710 ecx=0x08073704
edx=0x08073714
2020.06.19-16:58:[email protected]:
2020.06.19-16:58:[email protected]: maps:
2020.06.19-16:58:[email protected]: 08048000-08056000 r-xp 00000000 00:0c 1034
/nova/bin/sniffer
2020.06.19-16:58:[email protected]: 77730000-77765000 r-xp 00000000 00:0c 964
/lib/libuClibc-0.9.33.2.so
2020.06.19-16:58:[email protected]: 77769000-77783000 r-xp 00000000 00:0c 960
/lib/libgcc_s.so.1
2020.06.19-16:58:[email protected]: 77784000-77793000 r-xp 00000000 00:0c 944
/lib/libuc++.so
2020.06.19-16:58:[email protected]: 77794000-7779c000 r-xp 00000000 00:0c 950
/lib/libubox.so
2020.06.19-16:58:[email protected]: 7779d000-777e9000 r-xp 00000000 00:0c 946
/lib/libumsg.so
2020.06.19-16:58:[email protected]: 777ef000-777f6000 r-xp 00000000 00:0c 958
/lib/ld-uClibc-0.9.33.2.so
2020.06.19-16:58:[email protected]:
2020.06.19-16:58:[email protected]: stack: 0x7f8e0000 - 0x7f8df3e0
2020.06.19-16:58:[email protected]: 3c ab 05 08 04 00 fe 08 e0 0f 00 00 14 37 07
08 24 7a 05 08 00 00 00 00 18 f4 8d 7f 04 7a 05 08
2020.06.19-16:58:[email protected]: 08 00 00 00 24 7a 05 08 04 00 00 00 00 00 00
00 70 4a 7a 77 e4 9a 7e 77 38 f4 8d 7f e4 9a 7e 77
2020.06.19-16:58:[email protected]:
2020.06.19-16:58:[email protected]: code: 0x8050dac
2020.06.19-16:58:[email protected]: 8b 43 04 83 e0 fc 85 c0 74 1c 8b 4b 14 39 34
08

This vulnerability was initially found in long-term 6.46.3, and it seems
that the latest version stable 6.48.2 still suffers from this vulnerability.

4. CVE-2020-20237
The sniffer process suffers from a memory corruption vulnerability. By
sending a crafted packet, an authenticated remote user can crash the
sniffer process due to invalid memory access.

Against stable 6.46.5, the poc resulted in the following crash dump.

# cat /rw/logs/backtrace.log
2020.06.19-17:58:[email protected]:
2020.06.19-17:58:[email protected]:
2020.06.19-17:58:[email protected]: /nova/bin/sniffer
2020.06.19-17:58:[email protected]: --- signal=11
--------------------------------------------
2020.06.19-17:58:[email protected]:
2020.06.19-17:58:[email protected]: eip=0x77712055 eflags=0x00010202
2020.06.19-17:58:[email protected]: edi=0x77720f34 esi=0x77721015 ebp=0x7ff96b38
esp=0x7ff96af8
2020.06.19-17:58:[email protected]: eax=0x77721054 ebx=0x7771f000 ecx=0x77721034
edx=0x77721014
2020.06.19-17:58:[email protected]:
2020.06.19-17:58:[email protected]: maps:
2020.06.19-17:58:[email protected]: 08048000-08056000 r-xp 00000000 00:0c 1034
/nova/bin/sniffer
2020.06.19-17:58:[email protected]: 776e9000-7771e000 r-xp 00000000 00:0c 964
/lib/libuClibc-0.9.33.2.so
2020.06.19-17:58:[email protected]: 77722000-7773c000 r-xp 00000000 00:0c 960
/lib/libgcc_s.so.1
2020.06.19-17:58:[email protected]: 7773d000-7774c000 r-xp 00000000 00:0c 944
/lib/libuc++.so
2020.06.19-17:58:[email protected]: 7774d000-77755000 r-xp 00000000 00:0c 950
/lib/libubox.so
2020.06.19-17:58:[email protected]: 77756000-777a2000 r-xp 00000000 00:0c 946
/lib/libumsg.so
2020.06.19-17:58:[email protected]: 777a8000-777af000 r-xp 00000000 00:0c 958
/lib/ld-uClibc-0.9.33.2.so
2020.06.19-17:58:[email protected]:
2020.06.19-17:58:[email protected]: stack: 0x7ff97000 - 0x7ff96af8
2020.06.19-17:58:[email protected]: 00 f0 71 77 00 0f 72 77 30 00 00 00 00 00 00
00 38 b2 05 08 34 0f 72 77 04 00 00 00 00 0f 72 77
2020.06.19-17:58:[email protected]: 20 00 00 00 1b 7b 71 77 e8 f1 71 77 98 00 00
00 01 00 00 00 ec c4 74 77 74 a1 05 08 f8 6b f9 7f
2020.06.19-17:58:[email protected]:
2020.06.19-17:58:[email protected]: code: 0x77712055
2020.06.19-17:58:[email protected]: 89 14 10 eb bc 8b 93 a4 ff ff ff 8b 7d e0 8b
42

Interestingly, the same poc resulted in another different crash
dump(SIGABRT) against stable 6.48.2.

# cat /rw/logs/backtrace.log
2021.05.07-16:02:[email protected]:
2021.05.07-16:02:[email protected]:
2021.05.07-16:02:[email protected]: /nova/bin/sniffer
2021.05.07-16:02:[email protected]: --- signal=6
--------------------------------------------
2021.05.07-16:02:[email protected]:
2021.05.07-16:02:[email protected]: eip=0x776f255b eflags=0x00000246
2021.05.07-16:02:[email protected]: edi=0x0805aca8 esi=0x776fa200 ebp=0x7f97def8
esp=0x7f97def0
2021.05.07-16:02:[email protected]: eax=0x00000000 ebx=0x000000b6 ecx=0x000000b6
edx=0x00000006
2021.05.07-16:02:[email protected]:
2021.05.07-16:02:[email protected]: maps:
2021.05.07-16:02:[email protected]: 08048000-08056000 r-xp 00000000 00:0c 1036
/nova/bin/sniffer
2021.05.07-16:02:[email protected]: 776c4000-776f9000 r-xp 00000000 00:0c 966
/lib/libuClibc-0.9.33.2.so
2021.05.07-16:02:[email protected]: 776fd000-77717000 r-xp 00000000 00:0c 962
/lib/libgcc_s.so.1
2021.05.07-16:02:[email protected]: 77718000-77727000 r-xp 00000000 00:0c 945
/lib/libuc++.so
2021.05.07-16:02:[email protected]: 77728000-77730000 r-xp 00000000 00:0c 951
/lib/libubox.so
2021.05.07-16:02:[email protected]: 77731000-7777d000 r-xp 00000000 00:0c 947
/lib/libumsg.so
2021.05.07-16:02:[email protected]: 77783000-7778a000 r-xp 00000000 00:0c 960
/lib/ld-uClibc-0.9.33.2.so
2021.05.07-16:02:[email protected]:
2021.05.07-16:02:[email protected]: stack: 0x7f97f000 - 0x7f97def0
2021.05.07-16:02:[email protected]: 00 a0 6f 77 00 a0 6f 77 30 df 97 7f 77 e0 6e
77 06 00 00 00 00 a2 6f 77 20 00 00 00 00 00 00 00
2021.05.07-16:02:[email protected]: 26 2b 6f 77 00 a0 6f 77 28 df 97 7f 21 2c 6f
77 e8 a1 6f 77 00 a0 6f 77 00 bf 6f 77 a8 ac 05 08
2021.05.07-16:02:[email protected]:
2021.05.07-16:02:[email protected]: code: 0x776f255b
2021.05.07-16:02:[email protected]: 5b 3d 00 f0 ff ff 76 0e 8b 93 cc ff ff ff f7
d8

This vulnerability was initially found in long-term 6.46.3, and it seems
that the latest stable version 6.48.2 suffers from an assertion failure
vulnerability when running the same poc.


Solution
========

No upgrade firmware available yet


References
==========

[1] https://mikrotik.com/download/changelogs/stable-release-tree


 

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Thanks for everything Templateism - You should have written the code a little more complicated