Malicious PDF — malware analysis report

Static analysis result for SHA-256 27be5ef417bffd83…

MALICIOUS

PDF

33.7 KB Created: 2021-07-05 08:54:14 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-18
MD5: da861dffa406d1e094f6df9019a3e92c SHA-1: abee6512c36cec8ab687985d615bde83b68fe796 SHA-256: 27be5ef417bffd835693c96b1575b43f058844f27d66d8a7c29f2a7ad69f979a
142 Risk Score

Malware Insights

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

The PDF document contains numerous links, including one to 'netcdn.tw', which is flagged as a lure for game hacks. The heuristic 'PDF_SEO_LINK_FARM' indicates a large number of external links, suggesting a link farm designed to attract traffic. The ML classifier also strongly indicates maliciousness. The overall pattern suggests the PDF is used to redirect users to potentially malicious sites that may host further exploits or phishing content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

Heuristics 5

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • PDF links to a 'free generator / game hack' redirector high 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.
  • 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
  • External URI info PDF_URI
    PDF contains an external URL action
  • 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/431946152/free-andrbirds-head-roblox-game-hack PDF link annotation
    • https://delsys.com.tw/image/data/files/robux-get-com_GM431946152.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/how-to-get-free-robux-button_GM431946152.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/hack-coin-master-spin-android_GM406889139.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/free-robux-roblox-promo-codes_GM431946152.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/free-coins-coin-master-hack_GM406889139.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/xex-cheat-roblox_GM431946152.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/how-to-get-20210-robux-for-free_GM431946152.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/free-robux-no-human-verification-or-survey-2021_GM431946152.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/how-to-get-free-robux-2021-no-human-verification_GM431946152.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/roblox-free-robux_GM431946152.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/coinmaster_GM406889139.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/where-to-get-free-robux_GM431946152.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/coin-master-support_GM406889139.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/free-robux-codes-real-2021_GM431946152.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/minecraft-java-edition-redeem-code-free-2021_GM479516143.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/i-got-hacked-on-roblox_GM431946152.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/pokemon-go-free-evolve-with-trade_GM1094591345.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/free-robux-hacks-no-verification_GM431946152.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/minecraft-toys-for-free_GM479516143.pdfIn PDF document text
    • https://delsys.com.tw/image/data/files/minecraft-java-server-hosting-free_GM479516143.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
font_00_sfnt_off00002cd4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x2CD4 22468 bytes
SHA-256: 4bdf963453c4fe49ea0733945497ff9bb3d303e3300debf46d1c14735fbd215f
font_01_sfnt_off00005ee4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x5EE4 18944 bytes
SHA-256: 53a37ed702d1644caad71e030ffdc5e92daae9060fa0927eb973026e987afb99

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