Malicious PDF — malware analysis report

Static analysis result for SHA-256 97dca2779f1bcb8b…

MALICIOUS

PDF

118.5 KB
MD5: cb622b3bb9c9ad4119aa1f4f38ccd207 SHA-1: 626954ce29aab9b27601e7b12976fd933f6d0407 SHA-256: 97dca2779f1bcb8bb6f34a886e8eada097ec89d2be368f9c6c89dd563d1a51be
166 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including 'PDF_JAVASCRIPT', 'PDF_JS', and 'PDF_EVAL'. A critical ClamAV detection of 'Pdf.Exploit.Agent-36086' strongly suggests malicious intent. The JavaScript appears to be obfuscated and uses 'eval()' and 'String.fromCharCode()', common techniques for executing arbitrary code. The primary function of the script is likely to download and execute a second-stage payload.

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
517488c6fc1702667895793c738c72a41b55ca96ffc02b9b89b89e4c8cf44618
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627075 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
c516ce134a29bec17677c045ff2dfce83bf0383c579e823bd7018d2752135ed1
deobfuscated-js double percent-decoded annotation JavaScript at offset 0x143 262116 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 575 long base64-like blob(s).