Kingdom: Code Quality

Poor code quality leads to unpredictable behavior. From a user's perspective that often manifests itself as poor usability. For an attacker it provides an opportunity to stress the system in unexpected ways.

Memory Leak: Reallocation

C/C++
COBOL

Abstract

The program resizes a block of allocated memory. If the resize fails, the original block will be leaked.

Explanation

Memory leaks have two common and sometimes overlapping causes:

- Error conditions and other exceptional circumstances.

- Confusion over which part of the program is responsible for freeing the memory.

Most memory leaks result in general software reliability problems, but if an attacker can intentionally trigger a memory leak, the attacker may be able to launch a denial of service attack (by crashing the program) or take advantage of other unexpected program behavior resulting from a low memory condition [1].

Example 1: The following C function leaks a block of allocated memory if the call to realloc() fails to resize the original allocation.


char* getBlocks(int fd) {
  int amt;
  int request = BLOCK_SIZE;
  char* buf = (char*) malloc(BLOCK_SIZE + 1);
  if (!buf) {
    goto ERR;
  }
  amt = read(fd, buf, request);
  while ((amt % BLOCK_SIZE) != 0) {
     if (amt < request) {
        goto ERR;
     }
     request = request + BLOCK_SIZE;
     buf = realloc(buf, request);
     if (!buf) {
        goto ERR;
     }
     amt = read(fd, buf, request);
  }

  return buf;

  ERR:
  if (buf) {
    free(buf);
  }
  return NULL;
}

References

[1] J. Whittaker and H. Thompson How to Break Software Security Addison Wesley

[2] Standards Mapping - Common Weakness Enumeration CWE ID 401

[3] Standards Mapping - DISA Control Correlation Identifier Version 2 CCI-001094

[4] Standards Mapping - General Data Protection Regulation (GDPR) Indirect Access to Sensitive Data

[5] Standards Mapping - Motor Industry Software Reliability Association (MISRA) C Guidelines 2012 Rule 21.3

[6] Standards Mapping - Motor Industry Software Reliability Association (MISRA) C Guidelines 2023 Rule 21.3

[7] Standards Mapping - Motor Industry Software Reliability Association (MISRA) C++ Guidelines 2008 Rule 18-4-1

[8] Standards Mapping - NIST Special Publication 800-53 Revision 4 SC-5 Denial of Service Protection (P1)

[9] Standards Mapping - NIST Special Publication 800-53 Revision 5 SC-5 Denial of Service Protection

[10] Standards Mapping - OWASP Mobile Application Security Verification Standard 2.0 MASVS-STORAGE-2

[11] Standards Mapping - OWASP Top 10 2004 A9 Application Denial of Service

[12] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 Requirement 6.5.9

[13] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP6080 CAT II

[14] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP6080 CAT II

[15] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP6080 CAT II

[16] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP6080 CAT II

[17] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP6080 CAT II

[18] Standards Mapping - Security Technical Implementation Guide Version 3.9 APP6080 CAT II

[19] Standards Mapping - Security Technical Implementation Guide Version 3.10 APP6080 CAT II

[20] Standards Mapping - Security Technical Implementation Guide Version 4.2 APSC-DV-002400 CAT II

[21] Standards Mapping - Security Technical Implementation Guide Version 4.3 APSC-DV-002400 CAT II

[22] Standards Mapping - Security Technical Implementation Guide Version 4.4 APSC-DV-002400 CAT II

[23] Standards Mapping - Security Technical Implementation Guide Version 4.5 APSC-DV-002400 CAT II

[24] Standards Mapping - Security Technical Implementation Guide Version 4.6 APSC-DV-002400 CAT II

[25] Standards Mapping - Security Technical Implementation Guide Version 4.7 APSC-DV-002400 CAT II

[26] Standards Mapping - Security Technical Implementation Guide Version 4.8 APSC-DV-002400 CAT II

[27] Standards Mapping - Security Technical Implementation Guide Version 4.9 APSC-DV-002400 CAT II

[28] Standards Mapping - Security Technical Implementation Guide Version 4.10 APSC-DV-002400 CAT II

[29] Standards Mapping - Security Technical Implementation Guide Version 4.11 APSC-DV-002400 CAT II

[30] Standards Mapping - Security Technical Implementation Guide Version 4.1 APSC-DV-002400 CAT II

[31] Standards Mapping - Security Technical Implementation Guide Version 5.1 APSC-DV-002400 CAT II

[32] Standards Mapping - Security Technical Implementation Guide Version 5.2 APSC-DV-002400 CAT II

[33] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-002400 CAT II

[34] Standards Mapping - Security Technical Implementation Guide Version 6.1 APSC-DV-002400 CAT II

[35] Standards Mapping - Web Application Security Consortium Version 2.00 Denial of Service (WASC-10)

[36] Standards Mapping - Web Application Security Consortium 24 + 2 Denial of Service

desc.controlflow.cpp.memory_leak_reallocation

Abstract

The program resizes a block of allocated memory. If the resize fails, the original block will be leaked.

Explanation

Memory leaks have two common and sometimes overlapping causes:

- Error conditions and other exceptional circumstances.

- Confusion over which part of the program is responsible for freeing the memory.

Most memory leaks result in general software reliability problems, but if an attacker can intentionally trigger a memory leak, the attacker might be able to launch a denial of service attack (by crashing the program) or take advantage of other unexpected program behavior resulting from a low memory condition [1].

Example 1: The following Micro Focus COBOL program leaks a block of allocated memory if the call to realloc() fails to resize the original allocation.


CALL "malloc" USING
    BY VALUE mem-size
    RETURNING mem-pointer
END-CALL

ADD 1000 TO mem-size

CALL "realloc" USING
    BY VALUE mem-pointer
    BY VALUE mem-size
    RETURNING mem-pointer
END-CALL

IF mem-pointer <> null
    CALL "free" USING
        BY VALUE mem-pointer
    END-CALL
END-IF