CVE-2022-20703Cisco Small Business RV Series Routers Stack-based Buffer Overflow Vulnerability
CVE-2022-20703 is a improper certificate validation in Cisco Small Business RV160, RV260, RV340, and RV345 Series Routers, rated high (8.0 on CVSS 3.1).
Why this priority: Exploited in the wild: listed in CISA's KEV catalog.
Published · Updated · NVD status: Analyzed
What it is
TLS certificates are not checked properly, so an attacker on the path can pose as the server. A buffer on the stack overflows, which can overwrite return addresses and hand an attacker control of execution.
How it is reached
An attacker can exploit it from the same local network segment, without an account, but someone has to act first, such as opening a file or following a link.
What an attacker gains
A successful attack can read the data it protects, change data or behaviour and take it offline. In practice, this kind of flaw lets an attacker read or tamper with traffic, or pass a forged message as genuine.
Is it being exploited?
CISA added it to the Known Exploited Vulnerabilities catalog on 2022-03-03: it is being exploited in the wild. It can be exploited automatically, at scale. EPSS estimates a 9.2% chance of exploitation activity in the next 30 days, higher than 95% of scored CVEs.
What to do
- Treat it as urgent: it is on CISA's KEV list. CISA's deadline for US federal agencies: 2022-03-17.
- No fixed version is listed yet. Find every place Cisco Small Business RV160, RV260, RV340, and RV345 Series Routers runs, watch the references for a fix, and plan a replacement if it is no longer supported.
- Segment the networks that can reach it.
- Warn the people who use it, and filter files and links on the way in.
- Check exposed instances for signs of compromise, not only for the version.
Description from NVD
Multiple vulnerabilities in Cisco Small Business RV160, RV260, RV340, and RV345 Series Routers could allow an attacker to do any of the following: Execute arbitrary code Elevate privileges Execute arbitrary commands Bypass authentication and authorization protections Fetch and run unsigned software Cause denial of service (DoS) For more information about these vulnerabilities, see the Details section of this advisory.
What this means for your architecture.
A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.
Components it touches
- Network edge devices: VPNs, firewalls, routers and gateways. They sit between the internet and internal networks, so a flaw in one is often the first step into everything behind it.
- Operating systems on servers, workstations or devices. Everything on the host inherits the flaw.
- TLS termination and service-to-service channels. The flaw sits on the network path between clients and services.
- Signature checks. The flaw sits on the network path between clients and services.
Trust boundaries in play
- Local network segment. The attacker must share a network segment with the target.
- People who open files and links. Mail, chat and browsers are the delivery path.
- On the network path between clients and services. An attacker who crosses it can read or tamper with traffic, or pass a forged message as genuine.
- Wherever native code reads untrusted data. An attacker who crosses it can crash the process, read memory, or in the worst case run code.
Questions to answer about your own systems
- Where does Cisco Small Business RV160, RV260, RV340, and RV345 Series Routers run in your systems, and at which version?
- Which network segments can reach them?
- What can it reach once compromised: which data stores, secrets and services?
Read more
Sources
- CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
- Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
- Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
- Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.