CWE-558: Use of getlogin() in Multithreaded Application

Extended Description

The getlogin() function returns a pointer to a string that contains the name of the user associated with the calling process. The function is not reentrant, meaning that if it is called from another process, the contents are not locked out and the value of the string can be changed by another process. This makes it very risky to use because the username can be changed by other processes, so the results of the function cannot be trusted.

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-558 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-558, Use of getlogin() in Multithreaded Application, throughout the product lifecycle. Derive review questions, static or dynamic checks, and negative tests from the CWE's causal behavior; define the components and lifecycle stages each check covers; and retain findings with enough evidence to distinguish the root cause from symptoms and impacts. Track escapes and false negatives, then improve the verification plan after every confirmed occurrence.

NIST SP 800-218 Secure Software Development Framework — National Institute of Standards and Technology

Address Use of getlogin() in Multithreaded Application during Architecture and Design

MITRE associates mitigation with Architecture and Design, and Implementation; documented detection approaches include Automated Static Analysis; recorded impacts include Modify Application Data, Bypass Protection Mechanism, and Other. Use these source-defined anchors to turn CWE-558 into implementation, review, and verification checks for the affected component.

CWE-558: Use of getlogin() in Multithreaded Application — MITRE CWE

Triage CWE-558 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-558, Use of getlogin() in Multithreaded Application, has evidence of exploitation in the wild. Confirm the CVE-to-CWE root-cause mapping independently before attaching the example, then capture the affected product, required action, and remediation deadline. A missing KEV match is not evidence that the weakness is unexploited, and a KEV entry must not be generalized to every occurrence of this CWE.

Known Exploited Vulnerabilities Catalog — Cybersecurity and Infrastructure Security Agency

Apply precise root-cause mapping to CWE-558

Apply MITRE's full root-cause mapping guidance when using CWE-558, Use of getlogin() in Multithreaded Application. Separate weakness language from attacker prerequisites and technical impact, check the entry's abstraction and vulnerability-mapping notes, and prefer the most specific Base or Variant supported by the evidence. Record the rejected alternatives and require an independent review before the mapping is used for remediation trends or program metrics.

CVE to CWE Root Cause Mapping Guidance — MITRE CWE

Validate CWE-558 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-558, Use of getlogin() in Multithreaded Application. Confirm the finding describes the causal weakness rather than an impact or attack pattern, compare the abstraction and mapping notes with plausible alternatives, and have a second reviewer challenge the selection. Preserve the evidence and reasoning so recurring defects can be measured against one consistent identifier.

CVE to CWE Root Cause Mapping Quick Tips — MITRE CWE

Frequently Asked Questions

What is CWE-558: Use of getlogin() in Multithreaded Application?+

CWE-558: Use of getlogin() in Multithreaded Application is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product uses the getlogin() function in a multithreaded context, potentially causing it to return incorrect values. The getlogin() function returns a pointer to a string that contains the name of the user associated with the calling process. The function is not reentrant, meaning that if it is called from another process, the contents are not locked out and the value of the string can be changed by another process. This makes it very risky to use because the username can be changed by other processes, so the results of the function cannot be trusted.

What are the security consequences of Use of getlogin() in Multithreaded Application?+

If exploited, CWE-558 (Use of getlogin() in Multithreaded Application) it can compromise Integrity, Access Control and Other, leading to outcomes such as Modify Application Data, Bypass Protection Mechanism and Other.

How do you prevent or mitigate Use of getlogin() in Multithreaded Application?+

Recommended mitigations for CWE-558 include: Using names for security purposes is not advised. Names are easy to forge and can have overlapping user IDs, potentially causing confusion or impersonation. Use getlogin_r() instead, which is reentrant, meaning that other processes are locked out from changing the username.

Which programming languages are affected by Use of getlogin() in Multithreaded Application?+

CWE-558 commonly affects C and C++. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.

What is the difference between a CWE and a CVE?+

A CWE (Common Weakness Enumeration) like CWE-558 describes a category of software weakness — the underlying flaw type. A CVE (Common Vulnerabilities and Exposures) identifies a specific, real-world vulnerability in a particular product. In short, a CWE is the kind of mistake, and a CVE is an instance of that mistake being found in software.

CWE-558: Use of getlogin() in Multithreaded Application

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