Malicious PDF — malware analysis report

Static analysis result for SHA-256 3f8c343d62a80b2f…

MALICIOUS

PDF

118.6 KB
MD5: b24889ff2102354043ac62503e7d641e SHA-1: 623072360a1f4bccd7f27bcc6cba84c905045550 SHA-256: 3f8c343d62a80b2f0f7d0daa16490eba94b4c10458cd33e487108efe84d26ecd
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF contains embedded JavaScript, including a large, comment-padded eval stager. This JavaScript is responsible for executing malicious code, as indicated by the 'eval()' call and 'String.fromCharCode' usage. The ClamAV detection 'Pdf.Exploit.Agent-36086' further confirms its malicious nature. The primary attack vector appears to be JavaScript execution within the PDF to deliver a secondary 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
700a9753ab84a35a4ed9abbe1aee725b168ece51ac8f35fa2c1d06e185017bf2
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627322 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
f08bec4b624e7228d9adef7caf83f29cc18cf0a66f358558e64ba05e516f92e6
deobfuscated-js double percent-decoded annotation JavaScript at offset 0x143 262144 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 527 long base64-like blob(s).