The product manages a group of objects or resources and performs a separate memory allocation for each object, but it does not properly limit the total amount of memory that is consumed by all of the combined objects.
While the product might limit the amount of memory that is allocated in a single operation for a single object (such as a malloc of an array), if an attacker can cause multiple objects to be allocated in separate operations, then this might cause higher total memory consumption than the developer intended, leading to a denial of service.
Threat Mapped score: 1.9
Industry: Finiancial
Threat priority: P3 - Important (Medium)
CVE: CVE-2020-36049
JavaScript-based packet decoder uses concatenation of many small strings, causing out-of-memory (OOM) condition
CVE: CVE-2019-20176
Product allocates a new buffer on the stack for each file in a directory, allowing stack exhaustion
CVE: CVE-2013-1591
Chain: an integer overflow (CWE-190) in the image size calculation causes an infinite loop (CWE-835) which sequentially allocates buffers without limits (CWE-1325) until the stack is full.
| Phase | Note |
|---|---|
| Implementation | N/A |
Intro: This example contains a small allocation of stack memory. When the program was first constructed, the number of times this memory was allocated was probably inconsequential and presented no problem. Over time, as the number of objects in the database grow, the number of allocations will grow - eventually consuming the available stack, i.e. "stack exhaustion." An attacker who is able to add elements to the database could cause stack exhaustion more rapidly than assumed by the developer.
Body: Since this uses alloca(), it allocates memory directly on the stack. If end_limit is large enough, then the stack can be entirely consumed.
// Gets the size from the number of objects in a database, which over time can conceivably get very large int end_limit = get_nmbr_obj_from_db(); int i; int *base = NULL; int *p =base; for (i = 0; i < end_limit; i++) { *p = alloca(sizeof(int *)); // Allocate memory on the stack p = *p; // // Point to the next location to be saved }