Malicious PDF — malware analysis report

Static analysis result for SHA-256 7ca5c54dc1441728…

MALICIOUS

PDF

14.5 KB
MD5: 10ee012f8e22c2834fc56ad9cd230572 SHA-1: c2d154867fce8caaef52874745153c8acd115ecb SHA-256: 7ca5c54dc14417288e89288ccf689e3f2686333b010091986e08536f86e64ec1
216 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

This PDF file contains obfuscated JavaScript that utilizes String.fromCharCode and eval() to execute its payload. The script reconstructs a string by subtracting 31 from character codes, then executes the result. This technique is commonly used to download and execute further malicious content, as indicated by the ClamAV detection and ML classifier. The presence of JavaScript points to T1059.007, and the overall execution flow suggests T1203. Given it's a PDF, T1566.001 is a likely initial access vector.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

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: Pdf.Exploit.Dropped-94 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Dropped-94
  • 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.
  • 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_obj0076_000.js
c28effae366bd4b2a63fe29aea090a07947ae4e73aa9efc1cf87e16e006e7288
pdf-javascript-stream PDF /JS object 76 at offset 0x38AA 144 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).