CVE-2020-29557
Published: 29 January 2021
Summary
CVE-2020-29557 is a critical-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Dlink Dir-825\/Ac. Its CVSS base score is 9.8 (Critical).
Operationally, ranked in the top 0.3% 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 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2020-29557 is a buffer overflow vulnerability (CWE-119) affecting the web interface on D-Link DIR-825 R1 devices running firmware versions through 3.0.1. The flaw was addressed in updates released on or after 2020-11-20. It carries a CVSS 3.1 base score of 9.8, reflecting network attackability, low complexity, and no required authentication or user interaction.
An unauthenticated attacker with network access to the device can send a crafted request to the web interface, triggering the overflow to execute arbitrary code. Successful exploitation grants full control of the affected router, enabling actions such as credential theft, traffic interception, or use as a pivot point into connected networks.
D-Link has published updated firmware for the DIR-825 R1 via its Russian support site. The vulnerability appears in CISA's catalog of known exploited vulnerabilities, confirming observed in-the-wild attacks.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2020-21920
Vulnerability details
An issue was discovered on D-Link DIR-825 R1 devices through 3.0.1 before 2020-11-20. A buffer overflow in the web interface allows attackers to achieve pre-authentication remote code execution.
- CWE(s)
- KEV Date Added
- 03 November 2021
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 requires validation of all input to the web interface, preventing the crafted requests that trigger the buffer overflow.
Mandates prompt application of the vendor firmware update that eliminates the buffer-overflow flaw.
Requires memory-protection mechanisms that can block exploitation of the overflow even if input validation fails.