CWE-401: Missing Release of Memory after Effective Lifetime
The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.
How it's found
Missing Release of Memory after Effective Lifetime is a specific, narrowly defined instance of a broader pattern. Testers confirm it with targeted code review and a proof-of-concept input that exercises the exact code path this weakness describes.
Consequences
- DoS: Crash, Exit, or Restart, DoS: Instability, DoS: Resource Consumption (CPU), DoS: Resource Consumption (Memory): Most memory leaks result in general product 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 or hanging the program) or take advantage of other unexpected program behavior resulting from a low memory condition.
- Reduce Performance
Mitigations
- Implementation: Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone. For example, glibc in Linux provides protection against free of invalid pointers. When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391]. To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.
- Architecture and Design: Use an abstraction library to abstract away risky APIs. Not a complete solution.
- Architecture and Design/Build and Compilation: Consider using the Boehm-Demers-Weiser garbage collector (bdwgc), which can help avoid leaks.
Where this fits in a TurboPentest engagement
This weakness is not covered by the automated black-box pentest. IntegSec pentesters cover it in a manual engagement.
Frequently asked questions
What is CWE-401?
The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.
How do you find Missing Release of Memory after Effective Lifetime?
Missing Release of Memory after Effective Lifetime is a specific, narrowly defined instance of a broader pattern. Testers confirm it with targeted code review and a proof-of-concept input that exercises the exact code path this weakness describes.
What is the impact of CWE-401?
DoS: Crash, Exit, or Restart, DoS: Instability, DoS: Resource Consumption (CPU), DoS: Resource Consumption (Memory): Most memory leaks result in general product 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 or hanging the program) or take advantage of other unexpected program behavior resulting from a low memory condition. Reduce Performance
Does TurboPentest test for Missing Release of Memory after Effective Lifetime?
This weakness is not covered by the automated black-box pentest. IntegSec pentesters cover it in a manual engagement.
Related CWEs
- Base weaknessCWE-772: Missing Release of Resource after Effective Lifetime
- Class weaknessCWE-404: Improper Resource Shutdown or Release
- Variant weaknessCWE-48: Path Equivalence: 'file name' (Internal Whitespace)
- Base weaknessCWE-170: Improper Null Termination
- Base weaknessCWE-369: Divide By Zero
- Variant weaknessCWE-382: J2EE Bad Practices: Use of System.exit()
Written and reviewed by
Michel Chamberland - Founder & CEO, IntegSec
CISSP, OSCP, OSCE, CEH, GIAC, CCSK · 20+ years in offensive security
Michel has spent 20+ years on offensive security teams including IBM X-Force Red and Trustwave SpiderLabs, leading penetration tests, red team engagements, and breach response for Fortune 500 customers. He is the founder of IntegSec and the architect of TurboPentest.
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