Malicious PDF — malware analysis report

Static analysis result for SHA-256 5c3c73a73c265286…

MALICIOUS

PDF

1.6 KB
MD5: 16b865c9a5922515677bcc1b9c011f6e SHA-1: 47ccb9065b462872daf45ce324abac08db0bc2d1 SHA-256: 5c3c73a73c26528666c66bc4214a0f413de72215dde4aef8d209e923db29fe20
216 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution

This PDF file contains obfuscated JavaScript code that utilizes eval() and String.fromCharCode(), indicating an attempt to exploit a vulnerability and execute arbitrary code. The ML classifier and ClamAV detection strongly suggest malicious intent. The JavaScript is designed to download and execute a second-stage payload, as evidenced by the heuristic firings related to JavaScript exploits.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 7

  • PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER
    PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
  • ClamAV: Heuristics.PDF.ObfuscatedNameObject critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Heuristics.PDF.ObfuscatedNameObject
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • 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.
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules. (matched inside decoded 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0009_000.js
9159009f0d157dd0918e0f2739c1e884b11ecd3a4bb0027d84f1242eb4f6c621
pdf-javascript-stream PDF /JS object 9 at offset 0xDC 3898 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).