CVE-2021-40655
Published: 24 September 2021
Summary
CVE-2021-40655 is a high-severity Incorrect Authorization (CWE-863) vulnerability in Dlink Dir-605L Firmware. Its CVSS base score is 7.5 (High).
Operationally, ranked in the top 0.2% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 AC-3 (Access Enforcement) and AC-17 (Remote Access).
Deeper analysis
CVE-2021-40655 is an information disclosure vulnerability affecting the D-Link DIR-605 B2 router running firmware version 2.01MT. The flaw resides in the /getcfg.php endpoint and stems from incorrect authorization (CWE-863), which fails to enforce proper access controls on configuration data.
An unauthenticated remote attacker can exploit the issue by sending a crafted POST request to the affected endpoint. Successful exploitation yields the device's administrative username and password, exposing sensitive credentials without requiring any user interaction or prior authentication.
The vulnerability is tracked in CISA's Known Exploited Vulnerabilities catalog, confirming observed in-the-wild exploitation. D-Link has published security bulletins addressing affected hardware, and public proof-of-concept material is available in repositories that demonstrate the request forgery technique.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-27829
Vulnerability details
An informtion disclosure issue exists in D-LINK-DIR-605 B2 Firmware Version : 2.01MT. An attacker can obtain a user name and password by forging a post request to the / getcfg.php page
- CWE(s)
- KEV Date Added
- 16 May 2024
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly enforces authorization checks on the /getcfg.php endpoint so that unauthenticated POST requests cannot retrieve administrative credentials.
Limits the privileges granted to unauthenticated or low-privilege sessions, reducing the impact of missing authorization on configuration data.
Requires explicit remote-access authorization policies and mechanisms that would block forged requests to the exposed management endpoint.