Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
CWE-192 Variante Incompleto
Integer Coercion Error
An integer coercion error occurs when a program incorrectly converts, extends, or truncates a number between different data types, leading to unexpected values.
Definição
What is CWE-192?
An integer coercion error occurs when a program incorrectly converts, extends, or truncates a number between different data types, leading to unexpected values.
These errors happen during operations like type casting or when moving values between different-sized integers (e.g., from a short to a long). While they often cause crashes or corrupt data, they can also create subtle logic flaws. For example, a miscalculated size check might later enable a buffer overflow, turning a data integrity issue into a serious security vulnerability.
Managing this at scale is difficult; an ASPM like Plexicus can help you track and remediate these flaws across your entire stack. While SAST tools catch the pattern, Plexicus uses AI to suggest the actual code fix, saving hours of manual work by pinpointing the risky type conversions and providing corrected code snippets.
Impacto no mundo real
Real-world CVEs caused by CWE-192
-
Chain: integer coercion error (CWE-192) prevents a return value from indicating an error, leading to out-of-bounds write (CWE-787)
Como os atacantes a exploram
Trajeto do atacante passo a passo
- 1
The following code is intended to read an incoming packet from a socket and extract one or more headers.
- 2
The code performs a check to make sure that the packet does not contain too many headers. However, numHeaders is defined as a signed int, so it could be negative. If the incoming packet specifies a value such as -3, then the malloc calculation will generate a negative number (say, -300 if each header can be a maximum of 100 bytes). When this result is provided to malloc(), it is first converted to a size_t type. This conversion then produces a large value such as 4294966996, which may cause malloc() to fail or to allocate an extremely large amount of memory (CWE-195). With the appropriate negative numbers, an attacker could trick malloc() into using a very small positive number, which then allocates a buffer that is much smaller than expected, potentially leading to a buffer overflow.
- 3
The following code reads a maximum size and performs validation on that size. It then performs a strncpy, assuming it will not exceed the boundaries of the array. While the use of "short s" is forced in this particular example, short int's are frequently used within real-world code, such as code that processes structured data.
- 4
This code first exhibits an example of CWE-839, allowing "s" to be a negative number. When the negative short "s" is converted to an unsigned integer, it becomes an extremely large positive integer. When this converted integer is used by strncpy() it will lead to a buffer overflow (CWE-119).
Exemplo de código vulnerável
Vulnerable C
The following code is intended to read an incoming packet from a socket and extract one or more headers.
DataPacket *packet;
int numHeaders;
PacketHeader *headers;
sock=AcceptSocketConnection();
ReadPacket(packet, sock);
numHeaders =packet->headers;
if (numHeaders > 100) {
ExitError("too many headers!");
}
headers = malloc(numHeaders * sizeof(PacketHeader);
ParsePacketHeaders(packet, headers); Exemplo de código seguro
Secure pseudo
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
const safe = validateAndEscape(input);
return executeWithGuards(safe);
} What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Lista de verificação de prevenção
How to prevent CWE-192
- Requirements A language which throws exceptions on ambiguous data casts might be chosen.
- Architecture and Design Design objects and program flow such that multiple or complex casts are unnecessary
- Implementation Ensure that any data type casting that you must used is entirely understood in order to reduce the plausibility of error in use.
Sinais de deteção
How to detect CWE-192
O Plexicus deteta automaticamente o CWE-192 e abre um PR de correção em menos de 60 segundos.
O Codex Remedium analisa cada commit, identifica esta fraqueza exata e entrega um pull request pronto para revisão com o patch. Sem tickets. Sem transferências.
Perguntas frequentes O que é o CWE-192?
Qual a gravidade do CWE-192?
Que linguagens ou plataformas são afetadas pelo CWE-192?
Como posso prevenir o CWE-192?
Como é que o Plexicus deteta e corrige o CWE-192?
Onde posso saber mais sobre o CWE-192?
Frequently asked questions
O que é o CWE-192?
An integer coercion error occurs when a program incorrectly converts, extends, or truncates a number between different data types, leading to unexpected values.
Qual a gravidade do CWE-192?
A MITRE classifica a probabilidade de exploração como Média — a exploração é realista mas normalmente requer condições específicas.
Que linguagens ou plataformas são afetadas pelo CWE-192?
MITRE lists the following affected platforms: C, C++, Java, C#.
Como posso prevenir o CWE-192?
A language which throws exceptions on ambiguous data casts might be chosen. Design objects and program flow such that multiple or complex casts are unnecessary
Como é que o Plexicus deteta e corrige o CWE-192?
O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-192 em cada commit. Quando é encontrada uma correspondência, o nosso agente Codex Remedium abre um PR de correção com o código corrigido, testes e um resumo de uma linha para o revisor.
Onde posso saber mais sobre o CWE-192?
A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/192.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.
Fraquezas relacionadas
Weaknesses related to CWE-192
CWE-681 Pai
Incorrect Conversion between Numeric Types
This vulnerability occurs when a program converts a value from one numeric type to another (like a 64-bit integer to a 32-bit integer) and…
CWE-194 Irmão
Unexpected Sign Extension
This vulnerability occurs when a signed number from a smaller data type is moved or cast to a larger type, causing its sign bit to be…
CWE-195 Irmão
Signed to Unsigned Conversion Error
This vulnerability occurs when a signed integer (which can hold negative values) is converted to an unsigned integer (which holds only…
CWE-196 Irmão
Unsigned to Signed Conversion Error
This vulnerability occurs when a program takes an unsigned integer and converts it directly to a signed integer. If the original unsigned…
CWE-197 Irmão
Numeric Truncation Error
A numeric truncation error happens when a program converts a number to a smaller data type, cutting off its higher-order bits and…
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