Vulnerability identifier: #VU27056

Vulnerability risk: Low

CVSSv3.1: 7.6 [CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:U/RC:C]

CVE-ID: CVE-2020-9276

CWE-ID: CWE-121

Exploitation vector: Local network

Exploit availability: No

Vulnerable software:
DSL-2640B
Hardware solutions / Routers & switches, VoIP, GSM, etc

Vendor: D-Link

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error in the "do_cgi()" function. A remote authenticated attacker on the local network can send a specially crafted HTTP request, trigger stack-based buffer overflow and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Note: Unauthenticated exploitation is possible by combining this vulnerability with CVE-2020-9277

This vulnerability affects devices with the following versions:

• Hardware version: B2
• Firmware version: ver.4.01

Mitigation
Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

Vulnerable software versions

DSL-2640B: 4.01

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External links
http://raelize.com/advisories/CVE-2020-9276_D-Link-DSL-2640B_do_cgi-buffer-overflow_v1.0.txt
http://raelize.com/posts/d-link-dsl-2640b-security-advisories/
http://www.dlink.com/en/security-bulletin

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the local network (LAN).

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.