ICSA-21-019-01: dnsmasq by Simon Kelley (Update A)
CISA advisory · released 2021-01-19
Source record Collected from CISA's CSAF advisory feed
- Distribution label in the document: TLP:WHITE
- Revision 5, 2025-05-06 (final)
CISA's summary
Summary: Security researchers discovered and disclosed seven vulnerabilities in the open-source DNS component "dnsmasq", also known as "DNSpooq" vulnerabilities (CVE-2020-25681 through CVE-2020-25687). Three vulnerabilities (CVE-2020-25684 through CVE-2020-25686) affect the validation of DNS responses and impact several SCALANCE and RUGGEDCOM devices as listed below. Siemens has released updates for several affected products and recommends to update to the latest versions. Siemens recommends specific countermeasures for products where updates are not available.
Products, as the advisory lists them
| Vendor | Product | Version |
|---|---|---|
| Siemens | RUGGEDCOM RM1224 | <V6.4 |
| Siemens | SCALANCE M-800 | <V6.4 |
| Siemens | SCALANCE S615 | <V6.4 |
| Siemens | SCALANCE SC-600 | <V2.1.3 |
| Siemens | SCALANCE W1750D | vers:all/* |
DeSpy has not checked any unit, hardware revision or firmware.
Vulnerabilities in this advisory
- CVE-2020-25684 — CVE-2020-25684 · CWE-290
Affected devices lack proper address/port check in the DNS reply_query function of dnsmasq. This could make it easier for remote off-path attackers to forge replies.
- CVE-2020-25685 — CVE-2020-25685 · CWE-290
Affected devices lack query resource name (RRNAME) checks in the DNS reply_query function of dnsmasq. This could allow a remote attacker to spoof DNS traffic that can lead to DNS cache poisoning.
- CVE-2020-25686 — CVE-2020-25686 · CWE-330
Affected devices lack sufficient entropy in dnsmasq to handle multiple DNS query requests from the same resource name (RRNAME). This could allow a remote attacker to spoof DNS traffic, using a birthday attack (RFC 5452), than can lead to DNS cache poisoning.
Acknowledgments, as the advisory lists them
- Siemens ProductCERT: reporting these vulnerabilities to CISA.
- Moshe Kol, Shlomi Oberman, JSOF: coordinated disclosure
- CERT Coordination Center (CERT/CC): coordination efforts
- Industrial Control System Cyber Emergency Response Team (ICS-CERT): coordination efforts
The advisory's legal notice
Siemens Security Advisories are subject to the terms and conditions contained in Siemens' underlying license terms or other applicable agreements previously agreed to with Siemens (hereinafter "License Terms"). To the extent applicable to information, software or documentation made available in or through a Siemens Security Advisory, the Terms of Use of Siemens' Global Website (https://www.siemens.com/terms_of_use, hereinafter "Terms of Use"), in particular Sections 8-10 of the Terms of Use, shall apply additionally. In case of conflicts, the License Terms shall prevail over the Terms of Use.
Sources
DeSpy's copy of this version is dated 2026-09-28.
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