CVE-2020-3566
Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability
Exploited in the wild. In CISA KEV since 2021‑11‑03. A vendor fix is available.
What to do
The vendor has published a fix. Version details are below where the sources state them.
- Cisco Systems Inc. Cisco IOS XRAffected: 6.3.2Upgrade to: not statedStated by: BDU
- Cisco Systems Inc. Cisco ASR 9000 Series Aggregation Services RoutersAffected: 6.4.2Upgrade to: not statedStated by: BDU
Versions as the sources state them. Full version matrix after sign-in
Coverage timeline
0 publishersAdded to CISA KEV catalog
Sourced from public security reporting — each date is when it was published, not when it happened.
What it is
From the CVE record
A vulnerability in the Distance Vector Multicast Routing Protocol (DVMRP) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to exhaust process memory of an affected device. The vulnerability is due to insufficient queue management for Internet Group Management Protocol (IGMP) packets. An attacker could exploit this vulnerability by sending crafted IGMP traffic to an affected device. A successful exploit could allow the attacker to cause memory exhaustion, resulting in instability of other processes. These processes may include, but are not limited to, interior and exterior routing protocols. Cisco will release software updates that address this vulnerability.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Listed as exploited in the wild since 2021-11-03.
US federal agencies must remediate by 2022-05-03.
Apply updates per vendor instructions.
- Public exploits
0 sources with a proof of concept or module.
Exploit links, PoCs and Metasploit modules after sign-in- EPSS
3.7% chance of exploitation activity in the next 30 days, which ranks it in the 90th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
- Attention now
Rising.
Lifecycle
7 events over 2126 days, from the signal feeds we watch.
- OpenVAS check added
- Patch availablerecord updated
- Added to CISA KEV
- Publishedweakness classified, att&ck mapped
Affected products
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Scored 8.6 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity LowNo special conditions — the attack can be reliably reproduced
- Privileges Required NoneNo authentication required — anyone can exploit this
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope ChangedThe exploit can affect other components (e.g. sandbox escape, host compromise from VM)
Impact if exploited
- Confidentiality NoneNo confidentiality impact
- Integrity NoneNo integrity impact
- Availability HighTotal denial of service — the component is completely unavailable
Weaknesses
ATT&CK techniques
Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.
Sources
Watch the software you run.
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We'll flag the next CVE, public exploit or patch for Cisco IOS XR, not every advisory. This one: actively exploited.
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