Malicious PDF — malware analysis report

Static analysis result for SHA-256 9cd3dc53420fd651…

MALICIOUS

PDF

118.6 KB
MD5: 823cbd264b951e9591d181de7b3c54ac SHA-1: b56e851a471edf3a9fceab97f10362aed490215f SHA-256: 9cd3dc53420fd651c1310c4a43f5d1bd7636a56db54220507805cca36108b5b2
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File T1566.002 Spearphishing Attachment

The PDF file contains embedded JavaScript that utilizes eval() and String.fromCharCode(), indicating an attempt to obfuscate malicious code. Heuristics suggest this JavaScript acts as a stager, likely downloading and executing a second-stage payload. The ClamAV detection 'Pdf.Exploit.Agent-36086' further confirms the malicious nature of the file, pointing towards a known exploit targeting PDF vulnerabilities.

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
f9386f02f5d0e2e49eeed65c610046fed6a565011b09633398638a2d7b80b54d
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627351 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).
stream_002_off0001d8a6.bin
f0b7dc3d5d45de138d3654dbec00611ba43d52f0c5f0eece44aba82275ed2a51
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1D8A6 200 bytes