Malicious PDF — malware analysis report

Static analysis result for SHA-256 d3fccd4ce4411f4b…

MALICIOUS

PDF

16.0 KB
MD5: 00eeb034e421a6f8c533b935b55288d6 SHA-1: 903c03b5deaeedc96fce7318f9ce2b8643c9ec08 SHA-256: d3fccd4ce4411f4b12b4bcce106ab9fcec5632dc682f6559b52b6cdd4d97c1ee
96 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF contains obfuscated JavaScript, flagged as a high-confidence dropper. The heuristics indicate that the script is designed to download and execute a second-stage payload, likely by leveraging embedded JavaScript streams and potentially exploiting PDF reader vulnerabilities. The presence of multiple deobfuscated JavaScript files further supports this multi-stage execution chain. The document body was unreadable, preventing a more specific content-based rationale.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 5

  • Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER
    PDF JavaScript shows 3 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_dashed_payload, repeated_pluginschk. This is strongly consistent with pre-2011 Adobe Reader PDF droppers — OpenAction JS reads encoded data from annotation subjects, decodes it through one or more hex / base-N loops, and invokes eval indirectly (method name built one character at a time). The actual CVE is hidden in the final decoded layer and is not visible via static analysis.
  • JavaScript action low PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • syncAnnotScan annotation-staging primitive low PDF_FOXIT_SYNCANNOTSCAN
    PDF JavaScript calls syncAnnotScan() — a no-op annotation-enumeration primitive used by exploit-kit JavaScript to stage payload reads from annotation /Subject fields before eval(). Not a vulnerable sink itself; rarely seen in legitimate PDFs. (matched in decompressed stream)
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0005_000.js
a3319192cac6d4dc4eeb6af2d736b0ffec979b23116a003bc7c23382761c32a5
pdf-javascript-stream PDF /JS object 5 at offset 0x148 733 bytes
legacy_pdfkit_stage_000.js
704564452fd218afdc89bfcaa79ca7649224180e5d1c8a73060024d47ae241c4
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1B50 12653 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
deobfuscated.js
f02bb0c63a4b49989ed3cf25078a83b51ecb1d457a12e774d0b811cc6960247a
deobfuscated-js PDF JavaScript deobfuscation pass 113065 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).