CVE-2022-32138 - Unexpected Sign Extension

Severity

88%

Complexity

27%

Confidentiality

98%

In multiple CODESYS products, a remote attacker may craft a request which may cause an unexpected sign extension, resulting in a denial-of-service condition or memory overwrite.

CVSS 3.1 Base Score 8.8. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

CVSS 2.0 Base Score 6.5. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (AV:N/AC:L/Au:S/C:P/I:P/A:P).

Demo Examples

Unexpected Sign Extension

CWE-194

The following code reads a maximum size and performs a sanity check 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.


               
}
return(0x0000FFFF);
printf("Path is: %s\n", path);
DiePainfully("go away!\n");

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).

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