CWE-192 Variant Incomplete Medium likelihood

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.

Definition

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.
Auswirkungen in der Praxis

Real-world CVEs caused by CWE-192

  • CVE-2022-2639

    Chain: integer coercion error (CWE-192) prevents a return value from indicating an error, leading to out-of-bounds write (CWE-787)

Wie Angreifer es ausnutzen

Angreiferpfad Schritt für Schritt

  1. 1

    The following code is intended to read an incoming packet from a socket and extract one or more headers.

  2. 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. 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. 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).

Verwundbares Codebeispiel

Vulnerable C

The following code is intended to read an incoming packet from a socket and extract one or more headers.

Verwundbar C 
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);
Sicheres Codebeispiel

Secure pseudo

Sicher 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.
Präventions-Checkliste

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.
Erkennungssignale

How to detect CWE-192

Automated Static Analysis High

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.)

Plexicus Auto-Fix

Plexicus erkennt CWE-192 automatisch und öffnet in unter 60 Sekunden einen Fix-PR.

Codex Remedium scannt jeden Commit, identifiziert genau diese Schwachstelle und liefert einen reviewer-ready Pull Request mit dem Patch. Keine Tickets. Keine Hand-offs.

Demo anfordern Plexicus kostenlos testen
Häufig gestellte Fragen

Frequently asked questions

Was ist 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.

Wie gravierend ist CWE-192?

MITRE stuft die Exploit-Wahrscheinlichkeit als mittel ein — eine Ausnutzung ist realistisch, erfordert aber meist bestimmte Bedingungen.

Welche Sprachen oder Plattformen sind von CWE-192 betroffen?

MITRE lists the following affected platforms: C, C++, Java, C#.

Wie kann ich CWE-192 verhindern?

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

Wie erkennt und behebt Plexicus CWE-192?

Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-192 bei jedem Commit. Bei einem Treffer öffnet unser Codex-Remedium-Agent einen Fix-PR mit korrigiertem Code, Tests und einer einzeiligen Zusammenfassung für den Reviewer.

Wo erfahre ich mehr über CWE-192?

MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/192.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.

Verwandte Schwachstellen

Weaknesses related to CWE-192

CWE-681 Parent

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 Sibling

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 Sibling

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 Sibling

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 Sibling

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…

Ressourcen

Further reading

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