ATT&CK coverage › Technique

Hijack Execution Flow: Dynamic Linker Hijacking T1574.006

Adversaries may execute their own malicious payloads by hijacking environment variables the dynamic linker uses to load shared libraries. During the execution preparation phase of a program, the dynamic linker loads specified absolute paths of shared libraries from various environment variables and files, such as <code>LD_PRELOAD</code> on Linux or <code>DYLD_INSERT_LIBRARIES</code> on macOS. Libraries specified in environment variables are loaded first, taking precedence over system libraries with the same function name. Each platform's linker uses an extensive list of environment variables at different points in execution. These variables are often used by developers to debug binaries without needing to recompile, deconflict mapped symbols, and implement custom functions in the original library.

Events covered

1 catalog event are tagged with this technique by at least one rule.

ProviderEvent IDTitle
Sysmon11FileCreate

Authoring guide

Patterns shared across the 2 rules above: which fields they filter on, what specific values they look for, and what they exclude. Field names are normalized across vendors so Sigma's Image, Elastic's process.name, and Splunk's process_name collapse into one row. Each rule contributes at most once per row.

Fields filtered most (1 distinct)

The fields most rules look at when detecting this technique. The How column shows the operators authors use (eq, wildcard, regex_match, match) and how often each appears. Sample values are concrete examples to start from, not an exhaustive list.

FieldRulesHowSample values
TargetFilename2in 2"*\\.github\\workflows\\*.yaml", "*/.github/workflows/*.yaml", "*/.github/workflows/*.yml", "*\\.github\\workflows\\shai-hulud-workflow.yaml", "*\\.github\\workflows\\shai-hulud.yaml"

Top indicator values (20 distinct)

Specific (field, operator, value) combinations the rules check for, ranked by how many rules under this technique use each one. The Corpus reach column counts how many rules across the entire catalog (any technique) check the same combination. High numbers point to widely-used indicators that are likely noisy on their own; combine them with another condition for useful signal. Blank means the combination is specific to rules under this technique.

FieldKindValueRules (here)Corpus reach
TargetFilenamein"*\\.github\\workflows\\*.yaml"1
TargetFilenamein"*\\.github\\workflows\\*.yml"1
TargetFilenamein"*/.github/workflows/*.yaml"1
TargetFilenamein"*/.github/workflows/*.yml"1
TargetFilenamein"*\\.github\\workflows\\shai-hulud-workflow.yml"1
TargetFilenamein"*/.github/workflows/shai-hulud-workflow.yaml"1
TargetFilenamein"*\\.github\\workflows\\shai-hulud-workflow.yaml"1
TargetFilenamein"*\\.github\\workflows\\formatter_*.yaml"1
TargetFilenamein"*/.github/workflows/discussion.yml"1
TargetFilenamein"*/.github/workflows/formatter_*.yaml"1
TargetFilenamein"*/.github/workflows/shai-hulud.yaml"1
TargetFilenamein"*\\.github\\workflows\\discussion.yaml"1
TargetFilenamein"*\\.github\\workflows\\discussion.yml"1
TargetFilenamein"*/.github/workflows/discussion.yaml"1
TargetFilenamein"*/.github/workflows/shai-hulud.yml"1
TargetFilenamein"*\\.github\\workflows\\formatter_*.yml"1
TargetFilenamein"*\\.github\\workflows\\shai-hulud.yaml"1
TargetFilenamein"*/.github/workflows/formatter_*.yml"1
TargetFilenamein"*/.github/workflows/shai-hulud-workflow.yml"1
TargetFilenamein"*\\.github\\workflows\\shai-hulud.yml"1

Rules under this technique

Every rule in the catalog tagged with this technique, grouped by vendor. Click a rule title for its full predicates, exclusions, and indicators.

Splunk 2 rules