CVE Vulnerabilities

CVE-2021-27246

Stack-based Buffer Overflow

Published: Apr 14, 2021 | Modified: Apr 22, 2021
CVSS 3.x
8
HIGH
Source:
NVD
CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS 2.x
7.9 HIGH
AV:A/AC:M/Au:N/C:C/I:C/A:C
RedHat/V2
RedHat/V3
Ubuntu

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of TP-Link Archer A7 AC1750 1.0.15 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of MAC addresses by the tdpServer endpoint. A crafted TCP message can write stack pointers to the stack. An attacker can leverage this vulnerability to execute code in the context of the root user. Was ZDI-CAN-12306.

Weakness

A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).

Affected Software

Name Vendor Start Version End Version
Ac1750_firmware Tp-link 1.0.15 (including) 1.0.15 (including)

Potential Mitigations

  • 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 [REF-1334] discusses canary-based detection in detail.
  • Run or compile the software using features or extensions that randomly arrange the positions of a program’s executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code.
  • Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as “rebasing” (for Windows) and “prelinking” (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking.
  • For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].

References