N350RT: Stack-based Buffer Overflow
CVE-2023-7219 is a critical-severity stack-based buffer overflow vulnerability in N350RT from TOTOLINK, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected N350RT versions: 9.3.5u.6139_B202012. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.3% chance of exploitation within 30 days, higher than 71% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of N350RT you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| TOTOLINK | N350RT | 9.3.5u.6139_B202012 | Not stated |
| TOTOLINK | N350rt Firmware | 9.3.5u.6139_b20201216 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.2 | High | CNA (vuldb.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
| CVSS 2.0 | 8.3 | High | CNA (vuldb.com) |
Official description
A vulnerability has been found in Totolink N350RT 9.3.5u.6139_B202012 and classified as critical. Affected by this vulnerability is the function loginAuth of the file /cgi-bin/cstecgi.cgi. The manipulation of the argument http_host leads to stack-based buffer overflow. The attack can be launched remotely. The exploit has been disclosed to the public and may be used. The identifier VDB-249853 was assigned to this vulnerability. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Stack-based Buffer Overflow
The product writes past the end of a buffer that was allocated on the stack.
How developers prevent this class of flaw
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
- Use an abstraction library to abstract away risky APIs. Not a complete solution.
- Implement and perform bounds checking on input.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- vuldb.com/?ctiid.249853Permissions Required, Third Party Advisory
- vuldb.com/?id.249853Permissions Required, Third Party Advisory
Technical write-ups (may include proof of concept)
- github.com/jylsec/vuldb/blob/main/TOTOLINK/N350RT/5/README.mdExploit, Third Party Advisory
Other vulnerabilities in N350RT
- 9.8 Critical severity
- 8.8 High severity
- 9.1 Critical severity
- 7.2 High severity
- 8.8 High severity
- 8.8 High severity
Recent Stack-based Buffer Overflow vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 9.8 Critical severity
- 8.8 High severity
- 7.8 High severity
- 7.5 High severity
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