BF Specification of CVE-2018-14557 Tenda firmware until v15.03.06.44_CN(AC7), v15.03.05.19(6318)_CN(AC9), and v15.03.06.23_CN(AC10)
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//generated// Erroneous Code (in ‘__fastcall fronNatStaticSetting()’) to Declare in ‘char s;’ via Simple Data Type Primitive (while it shoud have been a structure - array of chars) in Codebase (int __fastcall fromNatStaticSetting(int a1)#L5) Bare-Metal (IoT Tenda routers AC7, 9, and 10 devices) leads to Wrong Type (char instead of array of chars) , which propagates to Wrong Type (in ‘sprintf(&s, “nat_static.asp?page=%s”,v6);’) Sequential Reposition (pointer) Stack Actual Codebase (function int __fastcall fromNatStaticSetting(int)#L16) in Bare-Metal (IoT Tenda routers AC7, 9, and 10 devices) that results in Overbound Pointer (’&s’) , which propagates to Overbound Pointer (in ‘sprintf(&s, “nat_static.asp?page=%s”,v6);’) Sequential Write (object) Moderate Stack Actual Codebase (function int __fastcall fromNatStaticSetting(int a1)#L16) in Bare-Metal (IoT Tenda routers AC7, 9, and 10 devices) that results in Buffer Overflow (’s’) , which can be exploited toward Denial of Service (DOS) (availability loss) security failure.
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| Class | Definition |
| Operation | Definition |
| Cause/Consequence | Definition |
| Code Bug | Code Bug type – An error in the implementation of an operation – proper operands over an improper operation. It is the roor cause of a security vulnerability. Must be fixed to resolve the vulnerability. |
| Erroneous Code | Erroneous Code bug - There is a coding error in the implementation of the operation. |
| Type | Type error (or fault) type – The set or range of allowed values of an entity is wrong or the operations allowed on them are wrong. |
| Wrong Type | Wrong Type error (or fault) – A data type range or structure is not correct. |
| Address Error/Fault | Address error (or fault) type – The address of an object is wrong. |
| Overbound Pointer | Overbound Pointer error (or fault) – Holds an address that is above the upper boundary of its object. |
| Memory Corruption/Disclosure Final Error | Memory Corruption/Disclosure final error/exploit vector type – An exploitable or undefined system behavior caused by memory addressing, allocation, use, or deallocation bugs. |
| Buffer Overflow | Buffer Overflow final error – Write data above the upper bound of an object (i.e., buffer over-write). |
| Operation Attribute | Definition |
| Mechanism | Mechanism operation attribute type – Shows how the operation with a bug or faulty operand is performed. |
| Simple | Simple operation attribute – The operation is via non-polymorphic types. |
| Sequential | Sequential operation attribute – The operation is via iterating over the object elements. |
| Source Code | Source Code operation attribute type – Shows where the code of the operation with a bug or faulty operand resides within the software, firmware, or hardware. |
| Codebase | Codebase operation attribute – The operation is in the programmer's code - in the application itself. |
| Execution Space | Execution Space operation attribute type – Shows where the operation with a bug or faulty operand is executed and the privilege level at which it runs. |
| Bare-Metal | Bare-Metal operation attribute – The bugged code runs in an environment without privilege control. Usually, the program is the only software running and has total access to the hardware. |
| Operand Attribute | Definition |
| Name Kind | Name Kind operand attribute type – Shows what the entity with this name is. |
| Data Type | Data Type operand attribute – A set of allowed values and the operations allowed over them. |
| Type Kind | Type Kind operand attribute type – Shows what the data type composition is. |
| Primitive | Primitive operand attribute – A scalar data type that mimics the hardware units - e.g., int (long, short, signed), float, double, string, Boolean. A primitive data type is only language defined and is not built from other data types. |
| Address State | Address State operand attribute type – Shows where the address is (i.e., its location) in the memory layout. |
| Stack | The object is a non-static local variable (defined in a function, a passed parameter, or a function return address). |
| Size Kind | Size Kind operand attribute type – Shows what is used as the size or length (i.e., the number of elements) of an object - e.g., as the limit for traversal over the elements. |
| Actual | Actual operand attribute – The real size or length (i.e., the number of elements) of the allocated memory for an object. |
| Address Kind | Address Kind operand attribute type - Shows how much memory is accessed (i.e., the span) outside of a bound of an object. |
| Moderate | Several bytes of memory is accessed. |