Malicious PDF — malware analysis report

Static analysis result for SHA-256 4bcd35a23d765195…

MALICIOUS

PDF

15.8 KB
MD5: 330cbd827a9f719d3b1b12eee34b8882 SHA-1: 6f69c36e41befc83fa8e8ff4d163ffd4d38241d2 SHA-256: 4bcd35a23d7651959943a721b9b0a910e725d6aaab84a70129b275a31164f3b4
156 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF contains obfuscated JavaScript, flagged by multiple heuristics as a dropper. The ML classifier and ClamAV detection strongly indicate malicious intent. The JavaScript is designed to download and execute a second-stage payload, as suggested by the 'PDF_JS_OBFUSCATED_DROPPER' heuristic. The specific ClamAV detection name 'Pdf.Dropper.Agent-7212217-0' is included as a primary IOC.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 6

  • ClamAV: Pdf.Dropper.Agent-7212217-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Dropper.Agent-7212217-0
  • 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
0bc2e68b5838477c7f7cf958aeac950e6293131ce4eeca3ba19dfabb51a79ee5
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1AEF 12656 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
e0c4580958812bbc0de417eded0ba0bf17f26af7928e299c8fb79cc3e7b86e1b
deobfuscated-js PDF JavaScript deobfuscation pass 67478 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).