Malicious PDF / .TXT — malware analysis report

Static analysis result for SHA-256 5f9744e5fe1350bc…

MALICIOUS

PDF / .TXT

4.1 KB
MD5: 4a43fc773d60eb9b2dffe23763139ef7 SHA-1: 17893f578012607665684be62595f3d1d80dc48a SHA-256: 5f9744e5fe1350bcb5d9bb454367f51bd549ef3299b2d3e7c8e3540717bed1f9
258 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains JavaScript that exploits CVE-2008-2992, a known vulnerability in Adobe Reader. The script decodes and evaluates obfuscated JavaScript, which in turn contains a URL to download a second-stage payload. The embedded URL http://93.174.93.11/~delmonca/u/load.php is highly suspicious and likely serves the malicious payload.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 9

  • 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)
  • 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.
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • PDF JavaScript shellcode contains an embedded download URL high PDF_JS_SHELLCODE_DOWNLOAD_URL
    Decoded PDF JavaScript shellcode contains a hardcoded http(s) URL stored as little-endian %uXXXX Unicode escapes. Reader exploit shellcode embeds the second-stage fetch URL this way and pulls it down with a urlmon/URLDownloadToFile-style download-and-execute (commodity downloader behaviour rather than a specific Acrobat CVE).
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://93.174.93.11/~delmonca/u/load.php

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0013_001.js
d13b0d8d0ea6dee69975ef1795ceb0759af77f97154b0751f29cbaa71f5a1124
pdf-javascript-stream PDF /JS object 13 at offset 0x368 6325 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
acroform_b64_00.js
de9e6e71262a4cbb96ede7019795711d4a8be874abbf6c4730839d1c8d8e84fd
deobfuscated-js PDF AcroForm base64 (decompressed) at offset 0x99D 3589 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
custom_b64_stage_000.js
85fe71200c33f398824631ccde606ec4fbbce8035fb8611c145accabab2137e1
deobfuscated-js custom Base64 decoded JavaScript layer 2 (PDF /JS object 13) at offset 0x95E 2025 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).