CVE-2021-40847
What it is
The update process of the Circle Parental Control Service on various NETGEAR routers allows remote attackers to achieve remote code execution as root via a MitM attack. While the parental controls themselves are not enabled by default on the routers, the Circle update daemon, circled, is enabled by default. This daemon connects to Circle and NETGEAR to obtain version information and updates to the circled daemon and its filtering database. However, database updates from NETGEAR are unsigned and downloaded via cleartext HTTP. As such, an attacker with the ability to perform a MitM attack on the device can respond to circled update requests with a crafted, compressed database file, the extraction of which gives the attacker the ability to overwrite executable files with attacker-controlled code. This affects R6400v2 1.0.4.106, R6700 1.0.2.16, R6700v3 1.0.4.106, R6900 1.0.2.16, R6900P 1.3.2.134, R7000 1.0.11.123, R7000P 1.3.2.134, R7850 1.0.5.68, R7900 1.0.4.38, R8000 1.0.4.68, and RS400 1.5.0.68.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 10.0% chance of exploitation in the next 30 days (EPSS). Higher than most.
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 10.0% in the next 30 days (EPSS).
- Severity: 8.1 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 10.0% · EPSS, next 30 days
- Weakness
- CWE-319 · Cleartext transmission
- Record status
- Modified
Affected
- Netgear r6400v2 Firmware 1.0.4.106
- Netgear r6700 Firmware 1.0.2.16
- Netgear r6700v3 Firmware 1.0.4.106
- Netgear r6900 Firmware 1.0.2.16
- Netgear r6900p Firmware 1.3.2.134
- Netgear r7000 Firmware 1.0.11.123
- Netgear r7000p Firmware 1.3.2.134
- Netgear r7850 Firmware 1.0.5.68
Attack profile CVSS 3.1 · 8.1
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2021-40847.md and follow it. Check whether this project is affected by CVE-2021-40847. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://kb.netgear.com/000064039/Security-Advisory-for-Remote-Code-Execution-on-Some-Routers-PSV-2021-0204
- https://kb.netgear.com/000064039/Security-Advisory-for-Remote-Code-Execution-on-Some-Routers-PSV-2021-0204
References
- https://blog.grimm-co.com/2021/09/mama-always-told-me-not-to-trust.html
- https://kb.netgear.com/000064039/Security-Advisory-for-Remote-Code-Execution-on-Some-Routers-PSV-2021-0204
- https://blog.grimm-co.com/2021/09/mama-always-told-me-not-to-trust.html
- https://kb.netgear.com/000064039/Security-Advisory-for-Remote-Code-Execution-on-Some-Routers-PSV-2021-0204