Certain NETGEAR devices are affected by a buffer overflow by an authenticated user. This affects R6700v3 before 1.0.4.98, R6400v2 before 1.0.4.98, R7000 before 1.0.11.106, R6900P before 1.3.2.124, R7000P before 1.3.2.124, R7900 before 1.0.4.26, R7850 before 1.0.5.60, R8000 before 1.0.4.58, RS400 before 1.5.0.48, R6400 before 1.0.1.62, R6700 before 1.0.2.16, R6900 before 1.0.2.16, MK60 before 1.0.5.102, MR60 before 1.0.5.102, MS60 before 1.0.5.102, CBR40 before 2.5.0.10, R8000P before 1.4.1.62, R7960P before 1.4.1.62, R7900P before 1.4.1.62, RAX15 before 1.0.1.64, RAX20 before 1.0.1.64, RAX75 before 1.0.3.102, RAX80 before 1.0.3.102, RAX200 before 1.0.2.102, RAX45 before 1.0.2.64, RAX50 before 1.0.2.64, EX7500 before 1.0.0.68, EAX80 before 1.0.1.62, EAX20 before 1.0.0.36, RBK752 before 3.2.16.6, RBK753 before 3.2.16.6, RBK753S before 3.2.16.6, RBK754 before 3.2.16.6, RBR750 before 3.2.16.6, RBS750 before 3.2.16.6, RBK852 before 3.2.16.6, RBK853 before 3.2.16.6, RBK854 before 3.2.16.6, RBR850 before 3.2.16.6, RBS850 before 3.2.16.6, RBR840 before 3.2.16.6, RBS840 before 3.2.16.6, R6120 before 1.0.0.70, R6220 before 1.1.0.100, R6230 before 1.1.0.100, R6260 before 1.1.0.76, R6850 before 1.1.0.76, R6350 before 1.1.0.76, R6330 before 1.1.0.76, D7800 before 1.0.1.58, RBK50 before 2.6.1.40, RBR50 before 2.6.1.40, RBS50 before 2.6.1.40, RBK40 before 2.6.1.36, RBR40 before 2.6.1.36, RBS40 before 2.6.1.38, RBK23 before 2.6.1.36, RBR20 before 2.6.1.38, RBS20 before 2.6.1.38, RBK12 before 2.6.1.44, RBK13 before 2.6.1.44, RBK14 before 2.6.1.44, RBK15 before 2.6.1.44, RBR10 before 2.6.1.44, RBS10 before 2.6.1.44, R6800 before 1.2.0.72, R6900v2 before 1.2.0.72, R6700v2 before 1.2.0.72, R7200 before 1.2.0.72, R7350 before 1.2.0.72, R7400 before 1.2.0.72, R7450 before 1.2.0.72, AC2100 before 1.2.0.72, AC2400 before 1.2.0.72, AC2600 before 1.2.0.72, R7800 before 1.0.2.74, R8900 before 1.0.5.24, R9000 before 1.0.5.24, RAX120 before 1.0.1.136, XR450 before 2.3.2.66, XR500 before 2.3.2.66, XR700 before 1.0.1.34, and XR300 before 1.0.3.50.
The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| R6700_firmware | Netgear | * | 1.0.4.98 (excluding) |
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer.
Be wary that a language’s interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Examples include the Safe C String Library (SafeStr) by Messier and Viega [REF-57], and the Strsafe.h library from Microsoft [REF-56]. These libraries provide safer versions of overflow-prone string-handling functions.
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.
Consider adhering to the following rules when allocating and managing an application’s memory:
Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
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].
Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX [REF-60] [REF-61]. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment.
For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND [REF-1336].
Run the code in a “jail” or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which files can be accessed in a particular directory or which commands can be executed by the software.
OS-level examples include the Unix chroot jail, AppArmor, and SELinux. In general, managed code may provide some protection. For example, java.io.FilePermission in the Java SecurityManager allows the software to specify restrictions on file operations.
This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise.
Be careful to avoid CWE-243 and other weaknesses related to jails.