CVE-2021-31886 Memory corruption in APOGEE MBC (PPC) (BACnet)
A stack-based buffer overflow in the FTP server allows remote attackers to execute arbitrary code or cause a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2021-31886?
CVE-2021-31886 is a critical memory corruption vulnerability in Siemens APOGEE MBC (PPC) (BACnet), published on 9 Nov 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability has been identified in APOGEE MBC (PPC) (BACnet) (All versions), APOGEE MBC (PPC) (P2 Ethernet) (All versions), APOGEE MEC (PPC) (BACnet) (All versions), APOGEE MEC (PPC) (P2 Ethernet) (All versions), APOGEE PXC Compact (BACnet) (All versions < V3.5.4), APOGEE PXC Compact (P2 Ethernet) (All versions < V2.8.19), APOGEE PXC Modular (BACnet) (All versions < V3.5.4), APOGEE PXC Modular (P2 Ethernet) (All versions < V2.8.19), Desigo PXC00-E.D (All versions >= V2.3 and < V6.30.016), Desigo PXC00-U (All versions >= V2.3 and < V6.30.016), Desigo PXC001-E.D (All versions >= V2.3 and < V6.30.016), Desigo PXC100-E.D (All versions >= V2.3 and < V6.30.016), Desigo PXC12-E.D (All versions >= V2.3 and < V6.30.016), Desigo PXC128-U (All versions >= V2.3 and < V6.30.016), Desigo PXC200-E.D (All versions >= V2.3 and < V6.30.016), Desigo PXC22-E.D (All versions >= V2.3 and < V6.30.016), Desigo PXC22.1-E.D (All versions >= V2.3 and < V6.30.016), Desigo PXC36.1-E.D (All versions >= V2.3 and < V6.30.016), Desigo PXC50-E.D (All versions >= V2.3 and < V6.30.016), Desigo PXC64-U (All versions >= V2.3 and < V6.30.016), Desigo PXM20-E (All versions >= V2.3 and < V6.30.016), Nucleus NET (All versions), Nucleus ReadyStart V3 (All versions < V2017.02.4), Nucleus Source Code (All versions), TALON TC Compact (BACnet) (All versions < V3.5.4), TALON TC Modular (BACnet) (All versions < V3.5.4). FTP server does not properly validate the length of the “USER” command, leading to stack-based buffer overflows. This may result in Denial-of-Service conditions and Remote Code Execution. (FSMD-2021-0010)
Which versions are affected by CVE-2021-31886?
It affects 22 products.
Products include Siemens Apogee Modular Building Controller Firmware, Siemens Apogee Modular Equiment Controller Firmware, Siemens Apogee Pxc Compact Firmware, Siemens Apogee Pxc Modular Firmware, Siemens Desigo Pxc00-E.d Firmware, Siemens Desigo Pxc00-U Firmware and 16 more.
How do I fix CVE-2021-31886?
No fix has been published for CVE-2021-31886 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2021-31886 being exploited?
There is no known exploitation of CVE-2021-31886 in the wild and no public exploit code.
Other vulnerabilities in Siemens APOGEE MBC (PPC) (BACnet)
- CVE-2021-31884 Memory corruption in APOGEE MBC (PPC) (BACnet)
- CVE-2021-31887 Memory corruption in APOGEE MBC (PPC) (BACnet)
- CVE-2021-31888 Memory corruption in APOGEE MBC (PPC) (BACnet)
- CVE-2022-38371 Denial of service in APOGEE MBC (PPC) (BACnet)
- CVE-2021-31346 Denial of service in Capital Embedded AR Classic 431-422
Sources
Also known as GHSA-p584-873g-v9x6.