Malicious PDF — malware analysis report

Static analysis result for SHA-256 cdffb2cc1df18277…

MALICIOUS

PDF

15.7 KB
MD5: 3ceb299fe12ec2303ec5e321305f9b4e SHA-1: bfa2a14d1ce8dd2ca0d027fc101c5acf6e444f7a SHA-256: cdffb2cc1df18277834246e9d85b681565468fc136d755be17a578198c51a5a9
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript/JScript T1204.002 Malicious Link/URL

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including PDF_JAVASCRIPT, PDF_JS, and PDF_EVAL. The presence of a 'Large comment-padded JavaScript eval stager' suggests an attempt to obfuscate malicious code. ClamAV detection as 'Pdf.Exploit.Agent-36086' strongly indicates malicious intent. The primary attack pattern involves exploiting PDF vulnerabilities to run this JavaScript, which is likely designed to download and execute further malicious content.

Heuristics 7

  • ClamAV: Pdf.Exploit.Agent-36086 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36086
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • Large comment-padded JavaScript eval stager high PDF_JS_LARGE_COMMENT_PADDED_EVAL
    PDF JavaScript contains a very large stream padded with long random-looking block comments around String.fromCharCode and eval. This is an exploit-kit obfuscation shape used to bury a decoder and recovered stage inside noise, not normal PDF form automation.
  • 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0006_000.js
83aba5b0e0b34ff8342de47df655e1f306da3f46e2d50be488747a2f48c118d4
pdf-javascript-stream PDF /JS object 6 at offset 0x143 425033 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 42 long base64-like blob(s).
legacy_pdfkit_stage_000.js
629fa7fbed1245b8b79a5d1264d143f09736df6f15eb06de7cae1967db4e3a60
deobfuscated-js double percent-decoded annotation JavaScript at offset 0x143 262144 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 640 long base64-like blob(s).