Malicious PDF — malware analysis report

Static analysis result for SHA-256 0b28fc48bb034447…

MALICIOUS

PDF

21.1 KB
MD5: e1826d1a030491a44194758d7a997de9 SHA-1: 9d37dffbe964bf4b85545e4665917c2fcdbda70b SHA-256: 0b28fc48bb0344471841267769eb8a7250ca94f95a4b531de2527dc751c1d3a4
270 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript that exploits CVE-2009-4324. This script is designed to download a second-stage payload from the URL http://mobisexonline.com/new/post.php?e=8&&. The presence of shellcode download URLs and critical heuristic firings strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 8

  • media.newPlayer — CVE-2009-4324 critical CVE exact CVE_2009_4324
    PDF JavaScript calls media.newPlayer — CVE-2009-4324 is a use-after-free in Adobe Reader's multimedia plugin triggered by media.newPlayer(). Actively exploited as a zero-day in December 2009. (identified after JavaScript deobfuscation)
  • ClamAV: Win.Trojan.Agent-36170 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Trojan.Agent-36170
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • 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.
  • 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://mobisexonline.com/new/post.php?e=8&&

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0008_000.js
84a4194b33b02565e5235d0840055494367812dd93c787983b8a17aef2f29836
pdf-javascript-stream PDF /JS object 8 at offset 0x1E7 1783 bytes
Detection
ClamAV: Win.Trojan.Agent-36170
Obfuscation or payload: unlikely
javascript_obj0008_001.js
c85041003545dd3c8fe8a3d2117186eac261723380e2f439a101881e2388fe6d
pdf-javascript-stream PDF /JS object 8 at offset 0x209 21111 bytes
Detection
ClamAV: Win.Trojan.Agent-36170
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
legacy_pdfkit_stage_000.js
74ec3cb337edf350b5765f62c42413691496f354b384663ed33c29ced9b105e0
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x912 1268 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
legacy_pdfkit_stage_001.js
42025b552c7960b53abcd8cd732b01c8d109eccfdfefc352b9826c4d5807d414
deobfuscated-js cross-stage annotation API aliases at offset 0x1E7 81 bytes