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name, description, domain, subdomain, tags, version, author, license, mitre_attack, d3fend, references
name description domain subdomain tags version author license mitre_attack d3fend references
analyzing-elf-binaries-on-linux Statically analyzes Linux ELF malware: ELF header and sections, dynamic symbols and imports, segment permissions, embedded strings, and packing indicators to infer capability without execution. Activates for requests to analyze an ELF binary, Linux malware, or shared object. cybersecurity malware-analysis
malware
static-analysis
elf
linux
symbols
entropy
1.0.0 analyst-ai-pack Apache-2.0
T1027
T1059.004
T1129
D3-FA
D3-FCR
ELF specification (System V ABI) — https://refspecs.linuxfoundation.org/elf/elf.pdf
pyelftools — https://github.com/eliben/pyelftools

Analyzing ELF Binaries on Linux

When to Use

  • You have a Linux executable or shared object and need to assess it statically.
  • You want to read the ELF header, segments, dynamic symbols, and strings to infer behavior.
  • You are checking for static linking, stripped symbols, or packing.

Do not use symbol absence as proof of nothing — stripped or statically linked Go/Rust binaries hide structure; switch to disassembly when static metadata is thin.

Prerequisites

  • readelf/nm/strings (binutils) or pyelftools (pip install pyelftools).
  • The sample in neutralized form inside the lab.

Safety & Handling

  • Static only: parse the file; do not set it executable or run it.

Workflow

Step 1: Read the ELF header

python scripts/analyst.py analyze sample.elf

Note class (ELF32/64), endianness, type (EXEC/DYN/REL), machine (x86-64, ARM, MIPS), and whether it is stripped.

Step 2: Examine segments and section permissions

Writable+executable segments, or a single large segment, suggest packing or self-modifying code. Compare PT_LOAD permissions against expectations.

Step 3: Inspect dynamic symbols and needed libraries

Imported functions hint at capability: socket/connect (network), ptrace (anti-debug or injection), fork/execve (process control), crypt/EVP_* (encryption).

Step 4: Detect static linking and packing

Static binaries lack a dynamic symbol table and NEEDED entries. High whole-file entropy and a tiny section table suggest a packer (e.g. UPX leaves UPX! markers).

Step 5: Skim strings and constructors

Check .init_array/constructors (code before main), and strings for paths, URLs, and shell commands.

Validation

  • Header type and segment permissions are consistent with the inferred behavior.
  • Imported symbols correspond to plausible capabilities.
  • Packing call (entropy + missing sections) matches the strings observed.

Pitfalls

  • Assuming dynamic symbols are complete — they only cover imported/exported names, not internal functions.
  • Treating a stripped Go binary as "empty"; its structure lives in runtime metadata, not the symbol table.
  • Ignoring constructors/.init_array, which run before main.

References