Malicious PDF — malware analysis report

Static analysis result for SHA-256 de880e1030d78e20…

MALICIOUS

PDF

42.9 KB Created: 2021-05-17 03:34:48 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-11-20
MD5: 52c367a3c8822027216c45878d0f0005 SHA-1: 96c16463c3d7a2dd41d4300e466374e11c70aafe SHA-256: de880e1030d78e203893ea43d3724a256f9c06ca2e1feef9507002d139a38535
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains malformed streams and links to known malicious redirectors, specifically promoting 'game hacks' and 'free generators'. The primary malicious URL identified is https://netcdn.xyz/app/406889139/daily-coin-master-spins-game-hack. While no scripts were explicitly extracted, the PDF structure and heuristic firings suggest exploitation of a client vulnerability to redirect the user to this malicious site, likely as part of a phishing or scam campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

Heuristics 5

  • 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.
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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 https://netcdn.xyz/app/406889139/daily-coin-master-spins-game-hack In PDF document text
    • http://ycstamping.com.tw/image/data/files/free-robux-by-watching-ads_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/real-free-robux-codes_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/how-to-get-100-free-spins-on-coin-master_GM406889139.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/free-coin-spin_GM406889139.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/minecraft-free-download-2021_GM479516143.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/coin-master-card-collection-link_GM406889139.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/robux-generators-that-actually-work_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/best-roblox-hacks_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/best-way-to-get-free-robux_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/coin-master-level-4_GM406889139.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/robux-generator-no-human-verification-2021_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/free-domain-for-minecraft-server_GM479516143.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/free-spin-link-coin-master_GM406889139.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/how-to-get-minecraft-for-free-on-xbox_GM479516143.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/roblox-apocalypse-rising-hack_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/coin-master-free-spins-link-no-verification-code_GM406889139.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/free-roblox-accounts-with-robux-that-work-2021_GM431946152.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/free-coin-master-spins-2021-link_GM406889139.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/minecraft-free-computer-game_GM479516143.pdfIn PDF document text
    • http://ycstamping.com.tw/image/data/files/are-there-any-coin-master-hacks-that-actually-work_GM406889139.pdfIn 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_003_off00004bc5.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4BC5 25564 bytes
SHA-256: 42fd0d68670d1ba7404ec72ec15868fec0fa9b5c41e3cccd89a24ed7b8addeea
font_01_sfnt_off000085d1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x85D1 18144 bytes
SHA-256: bc10b16e761ad325a331543066bfce6b0ff34f70478a358edc53294c2ec73427

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