Malicious PDF — malware analysis report

Static analysis result for SHA-256 7a65fc693aafb3a0…

MALICIOUS

PDF

118.6 KB
MD5: 646d96f42206be800cf0ed091f1505cd SHA-1: 1b7611cfc158f06843b3f05aebc25c7814c66e59 SHA-256: 7a65fc693aafb3a00701a1cb128ddb4d2a8991b6b706de854035ffa31af28187
166 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript, as indicated by multiple heuristic firings including 'PDF_JAVASCRIPT', 'PDF_JS', and 'PDF_JS_LARGE_COMMENT_PADDED_EVAL'. The presence of 'PDF_EVAL' and 'PDF_FROMCHARCODE' suggests code execution and obfuscation techniques. ClamAV detection as 'Pdf.Exploit.Agent-36086' strongly indicates malicious intent, likely involving the execution of a second-stage payload via the JavaScript.

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
4db5ddb161f0592d1c0353893a12d98f64c20f86da409b647527c58faacbecc6
pdf-javascript-stream PDF /JS object 6 at offset 0x143 626990 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
c0159503ab3090dcb2c0317b47bb97acdf255b16f6ad56d5e9e42febe605c65b
deobfuscated-js double percent-decoded annotation JavaScript at offset 0x143 262144 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 697 long base64-like blob(s).