Malicious PDF — malware analysis report

Static analysis result for SHA-256 8f8bb8a5a3035fb8…

MALICIOUS

PDF

4.2 KB
MD5: 7fcf451c14bfe709e93db7bb72fb3693 SHA-1: 5e4bf6574c4565342e5b1d8175bc625758380405 SHA-256: 8f8bb8a5a3035fb86457f3c35e7e4dc47a2f4172dfa02259cbd1a42c562392a3
126 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript/JScript T1204.002 Malicious File

The PDF file contains embedded JavaScript that utilizes eval() and String.fromCharCode, indicative of obfuscation. The critical CVE-2008-2992 heuristic firing confirms the exploitation of a known PDF vulnerability via util.printf and JavaScript execution. The embedded JavaScript streams, particularly the deobfuscated 'numeric_charcode_stage_000.js', are designed to execute malicious code, likely downloading and running a secondary payload. The lack of specific indicators for a known family leads to an 'unknown family' classification.

Heuristics 6

  • util.printf — CVE-2008-2992 critical CVE exact CVE_2008_2992
    PDF JavaScript calls util.printf() — CVE-2008-2992 is a stack buffer overflow in Adobe Reader triggered by a long format-specifier argument. Widely exploited in the wild after disclosure. (identified after JavaScript deobfuscation)
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • 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_obj0005_000.js
d2e7c297cf148b1f1091fc29ada81b3fd8bfc4314bd8a8fcc095e835f5e6731f
pdf-javascript-stream PDF /JS object 5 at offset 0x107 22588 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
numeric_charcode_stage_000.js
5ca4847fd69c91169d09988969225aa5224cd4c58ef57a8bcf0b76d151a7bac7
deobfuscated-js numeric char-code string decoded JavaScript at offset 0x115 6651 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).