Malicious PDF — malware analysis report

Static analysis result for SHA-256 9892d6f4bb0d5a1b…

MALICIOUS

PDF

15.7 KB
MD5: 3a1bf7e9038100b63bdaba7e53969b57 SHA-1: 9c454480702fe4084d6228d0827cecea8116d5f9 SHA-256: 9892d6f4bb0d5a1b0af648dd7d250ab55f5d26655356883e578ea504539eb8bb
166 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript, including a large comment-padded eval stager. This indicates an attempt to obfuscate and execute malicious code. The presence of `eval()` and `String.fromCharCode` calls within the JavaScript strongly suggests the execution of arbitrary code, likely to download and run a secondary payload. ClamAV detection as 'Pdf.Exploit.Agent-36086' further supports the malicious nature of the file.

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
e0cd92738fefc0983a5a9af50e607bbc402110f132b74dfb0105edf14220fd5c
pdf-javascript-stream PDF /JS object 6 at offset 0x143 425156 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
1965572f0191c64f9a998f03eec1efa4de8c6ed022a61bf533b179b1ae1ac3cf
deobfuscated-js double percent-decoded annotation JavaScript at offset 0x143 262092 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 453 long base64-like blob(s).