Heap Inspection

ABSTRACT

不要使用 realloc() 來調整儲存敏感信息的緩沖區大小。因為該函數可能會將敏感信息的副本遺留在內存中，而您又無法對這部分內存進行覆蓋。

EXPLANATION

當敏感數據（如密碼或加密密鑰）因為沒有從內存中刪除而被泄漏給攻擊者時，就會發生 Heap inspection 漏洞。

realloc() 函數通常用來提高某個分配的內存塊的大小。該操作經常要求將以前的內存塊中的內容復制到新的且更大的內存塊中。該操作會完整地保留原內存塊中的內容，但不允許程序進行訪問，這就使程序無法清除內存中的敏感數據。如果攻擊者能夠后期訪問某個內存轉儲中的內容，敏感數據就會暴露。



示例：以下代碼在一個包含敏感數據的緩沖區上調用了 realloc()：

cleartext_buffer = get_secret();
...
cleartext_buffer = realloc(cleartext_buffer, 1024);
...
scrub_memory(cleartext_buffer, 1024);

REFERENCES

[1] Standards Mapping - OWASP Top 10 2010 - (OWASP 2010) A7 Insecure Cryptographic Storage

[2] Standards Mapping - OWASP Top 10 2007 - (OWASP 2007) A8 Insecure Cryptographic Storage

[3] Standards Mapping - OWASP Top 10 2004 - (OWASP 2004) A8 Insecure Storage

[4] Standards Mapping - Security Technical Implementation Guide Version 3 - (STIG 3) APP3230.2 CAT II

[5] Standards Mapping - Security Technical Implementation Guide Version 3.4 - (STIG 3.4) APP3230.2 CAT II

[6] Standards Mapping - Common Weakness Enumeration - (CWE) CWE ID 244

[7] Standards Mapping - FIPS200 - (FISMA) MP

[8] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 - (PCI 1.2) Requirement 3.4, Requirement 6.3.1.3, Requirement 6.5.8, Requirement 8.4

[9] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 - (PCI 2.0) Requirement 3.4, Requirement 6.5.3, Requirement 8.4

[10] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 - (PCI 1.1) Requirement 3.4, Requirement 6.5.8, Requirement 8.4