Malicious PDF — malware analysis report

Static analysis result for SHA-256 0758ee36d7d3d00b…

MALICIOUS

PDF

118.7 KB
MD5: 290218951bb5975c5178259476226df9 SHA-1: b08baddebd3e197bba36b6b130a263457f34b07e SHA-256: 0758ee36d7d3d00b4e905e9c0c16ddeee5db00b8d62d110406e594cd15477c8b
256 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 eval() and String.fromCharCode(), indicating an attempt to execute malicious code. The presence of a 'PDF JavaScript exploit cluster' and 'Large comment-padded JavaScript eval stager' heuristics, along with ClamAV detection as 'Pdf.Exploit.Agent-36086', strongly suggests it's designed to exploit vulnerabilities and download further malicious content. The extracted JavaScript files are the primary indicators of this malicious behavior.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 8

  • 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.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
5e5c6b39c65603210659d0e52e18269065b4063e93691485f06fa7feb8bf0090
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627555 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
f53e49b7428ce7cf786ce67cdcf09a941528cd62fe452f9ef060b9a012716046
deobfuscated-js double percent-decoded annotation JavaScript at offset 0x143 262136 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 609 long base64-like blob(s).