Malicious PDF — malware analysis report

Static analysis result for SHA-256 c3496b56a0033f21…

MALICIOUS

PDF

16.2 KB
MD5: e744614eb2d8a62e897747a026c859b8 SHA-1: 67d04232f718c4b0e923a69ba1fdb130485b4d11 SHA-256: c3496b56a0033f2145586caeed8aaf64ae86339c1dde28a76eaef667623f1a59
96 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF contains obfuscated JavaScript, flagged as a high-confidence dropper. This script is designed to download and execute a second-stage payload, as indicated by the 'deobfuscated.js' and 'legacy_pdfkit_stage_000.js' artifacts. The ML classifier also strongly indicates maliciousness.

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
207b4685c302a81875f4b8e160db42515449048a7cb34316dd2bd9a84e123bb5
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1B98 12834 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
fec794d4aae73c91572c551f027e684171f7802489a690fdba1ee0a70798fa37
deobfuscated-js PDF JavaScript deobfuscation pass 112577 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).