BF Specification of CVE-2007-6429 Integer overflows in X.Org Xserver before 1.4.1
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Missing verifications of input values leads to use of a wrong argument in a memory size calculations and wraparounds , allowing allocation of not enough memory, which, when used leads to a buffer overflow. If exploited, this can lead to arbitrary code execution.
//generated// Missing Code to Verify in leads to Wrong Value
, which propagates to Wrong Argument Calculate in resulting in Wrap Around (integer overflow)
, which propagates to Wrong Size (in ‘xalloc()’ and ‘AshmFuncs()’) Allocate in resulting in Not Enough Memory
, which propagates to Not Enough Memory Write in resulting in Buffer Overflow
. If exploited this can lead to ACE (everything could be lost).
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| Class | Definition |
| DVR | Data Verification (DVR) class – Data are verified (i.e., semantics check) or corrected (i.e., assign or remove) improperly. |
| TCM | Type Computation (TCM) class – An arithmetic expression (over numbers, strings, or pointers) is calculated improperly, or a boolean condition is evaluated improperly. |
| MMN | Memory Management (MMN) class – An object is allocated, resized, or deallocated improperly. |
| MUS | Memory Use (MUS) class – An object is initialized, read, written, or cleared improperly. |
| Operation | Definition |
| Verify | Verify operation – Check data semantics (e.g., proper value/meaning) in order to accept (and possibly correct) or reject it. |
| Calculate | Calculate operation – Find the result of a numeric, pointer, or string operation. |
| Allocate | Allocate operation – Reserve space in memory for an object; defines its initial boundaries and size. |
| Write | Write operation – Change the data value of an object in memory to another meaningful value. |
| Cause/Consequence | Definition |
| Code Bug | Code Bug type – An error in the implementation of an operation – proper operands over an improper operation. A first cause for the chain of weaknesses underlying a software security vulnerability. Must be fixed to resolve the vulnerability. |
| Missing Code | Missing Code bug - The operation is entirely absent. |
| Data Error/Fault | Data Fault/Error type – The data of an object has harmed semantics or inconsistent or wrong value. |
| Wrong Value | Wrong Value fault/error – The data value is not accurate (e.g., outside of a range). |
| Wrong Argument | Wrong Argument fault/error – Inaccurate input data value, i.e., non-verified for harmed semantics. |
| Wrap Around | Wrap Around fault/error – A moved around-the-clock value over its data type upper or lower range, as it exceeds that range. (Integer Over-/Under-flow is a wrapped-around the upper/lower range integer value; may become very small/large and change to the opposite sign.) |
| Wrong Size | Wrong Size fault/error – The value used as size or length (i.e., the number of elements) does not match an object's memory size or length (e.g., to limit a pointer reposition or index increment/decrement in a repetition statement). |
| Size Error/Fault | Type Fault/Error type – The set or range of allowed values of an entity is wrong or the operations allowed on them are wrong. |
| Not Enough Memory | |
| Memory Corruption/Disclosure Final Error | Memory Corruption/Disclosure final error 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 overwrite). |
| Operation Attribute | Definition |
| Operand Attribute | Definition |