Buffer overflow in Wago Pfc200
CVE-2019-5186
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.0 (High). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.008 (56.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 56th percentile — 56.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000
Affected products
- Wago Pfc200
- Wago Pfc200 Firmware — versions 03.02.02\(14\), 03.02.02(14)
- Wago — versions WAGO PFC200 Firmware version 03.02.02(14)
Weakness classification (CWE)
References
- talosintelligence.com/vulnerability_reports/TALOS-2019-0966 (Exploit, Third Party Advisory, Mitigation)
Frequently asked questions
- What is CVE-2019-5186?
- CVE-2019-5186 is a high-severity vulnerability in Wago Pfc200, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 7.0/10. Published 2020-03-23.
- How severe is CVE-2019-5186?
- High severity. CVSS v3 base score is 7.0 out of 10.