CVE-2019-5186 Memory corruption in Wago

High 7.0 Published 23 Mar 2020 Updated 4 Aug 2024

A stack buffer overflow in the WAGO PFC 200 iocheckd service allows remote attackers to cause a denial of service or potentially execute arbitrary code via crafted packets.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: None listed

What is CVE-2019-5186?

CVE-2019-5186 is a high-severity memory corruption vulnerability in Wago, published on 23 Mar 2020. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

An exploitable stack buffer overflow vulnerability vulnerability exists in the iocheckd service "I/O-Check" functionality of WAGO PFC 200. An attacker can send a specially crafted packet to trigger the parsing of this cache file.At 0x1eb9c the extracted interface element name from the xml file is used as an argument to /etc/config-tools/config_interfaces interface=<contents of interface element> using sprintf(). The destination buffer sp+0x40 is overflowed with the call to sprintf() for any interface values that are greater than 512-len("/etc/config-tools/config_interfaces interface=") in length. Later, at 0x1ea08 strcpy() is used to copy the contents of the stack buffer that was overflowed sp+0x40 into sp+0x440. The buffer sp+0x440 is immediately adjacent to sp+0x40 on the stack. Therefore, there is no NULL termination on the buffer sp+0x40 since it overflowed into sp+0x440. The strcpy() will result in invalid memory access. An interface value of length 0x3c4 will cause the service to crash.

Weakness: CWE-787, CWE-120

Which versions are affected by CVE-2019-5186?

It affects 1 product.

Products include Wago Pfc200 Firmware.

How do I fix CVE-2019-5186?

No fix has been published for CVE-2019-5186 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-2019-5186 being exploited?

There is no known exploitation of CVE-2019-5186 in the wild and no public exploit code.

Sources

Also known as GHSA-ccp7-rf73-6pq2.