Malicious PDF — malware analysis report

Static analysis result for SHA-256 4638117142d45bd8…

MALICIOUS

PDF

31.1 KB Created: 2021-07-22 06:14:51 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-27
MD5: 3cb1c0112fea15aa5b3561705ed70f8c SHA-1: 55dd8c88efdeafe6423d9804307190140cc5eecb SHA-256: 4638117142d45bd83358a8841bba3adef6f1f4ddcb09bb5871a0fd95d7eb2db5
130 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document contains a critical heuristic firing for a redirector link, specifically luring users with a 'free generator / game hack'. The embedded URL, http://netcdn.tw/app/406889139/coin-master-free-gifts-game-hack, is known to lead to malicious infrastructure. The document body also contains a call-to-action phrase, reinforcing the lure.

Machine Learning

  • Nyx PDF Classifier clean score 0.0564

Heuristics 4

  • PDF links to a 'free generator / game hack' redirector critical PDF_GAME_HACK_REDIRECT_LURE
    PDF's clickable action targets a redirector of the form /app/<id>/<slug>-game-hack — the landing-page shape of a large SEO 'free spins / generator / game hack' lure family that funnels victims through rotating disposable hosts to a malware/scam payload. The multi-link variants also trip ML/link-farm rules; this catches the single-link variants that otherwise score clean. CRITICAL on its own: the /app/<id>/<slug>-game-hack path shape is unambiguous scam infra, and the host rotates so a host-list match can't be relied on.
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://netcdn.tw/app/406889139/coin-master-free-gifts-game-hack In PDF document text
    • http://en.wikipedia.org/wiki/MIT_LicenseIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_002_off00002522.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x2522 23320 bytes
SHA-256: 46626e07c56698d922ef3fbc75696cd08d76a0441cd5777904f60a1695f05931
font_01_sfnt_off000059c7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x59C7 17712 bytes
SHA-256: 401d56b29285354d6954c3c26e793cbeb56329cdc5209d9139ec018457d4ba23