Malicious PDF — malware analysis report

Static analysis result for SHA-256 6c21a62aee13f3ce…

MALICIOUS

PDF

48.3 KB Created: 2021-06-08 16:55:20 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-13
MD5: c3a06ac990844e4c9df6072a03c4b4fc SHA-1: 6b2317602e98c091dd9c3f78fa10e7f36a3314ee SHA-256: 6c21a62aee13f3ce14a48dcc8b81a33c987e166aa40ff5d01fe8581aef4d0f2d
200 Risk Score

Malware Insights

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

The PDF contains a critical heuristic firing for a redirector link that impersonates Microsoft and offers a 'game hack'. The document body, though heavily obfuscated, contains a URL that aligns with this lure. The presence of embedded URLs and the ML classifier's high confidence score indicate a malicious intent to redirect the user to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9871

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.
  • Brand-impersonation credential phishing lure high SE_BRAND_CREDENTIAL_PHISH
    Document impersonates a well-known consumer brand and uses account-security / verification language ('unusual activity', 'account on hold', 'verify your account') to steer the reader to a credential-harvesting link. Corroborated by: call-to-action link host does not match the impersonated brand: https://netcdn.tw/app/431946152/abstact-free-version-roblox-exploit-game-hack.
  • 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.tw/app/431946152/abstact-free-version-roblox-exploit-game-hack In PDF document text
    • https://www.gornjastubica.hr/files/2021-free-spins-coin-master_GM406889139.pdfIn PDF document text
    • http://gornjastubica.hr/files/feb-23-2021-free-coin-master-spins_GM406889139.pdfIn PDF document text
    • https://www.gornjastubica.hr/files/roblox-hacked-accounts-list_GM431946152.pdfIn PDF document text
    • http://gornjastubica.hr/files/free-roblox-hair-to-wear_GM431946152.pdfIn PDF document text
    • https://www.gornjastubica.hr/files/coin-master-gift-hack_GM406889139.pdfIn PDF document text
    • https://www.gornjastubica.hr/files/coin-master-free-gold-cards-link-2021ee-spins_GM406889139.pdfIn PDF document text
    • https://www.gornjastubica.hr/files/how-to-get-free-robux-2021-easy_GM431946152.pdfIn PDF document text
    • https://www.gornjastubica.hr/files/how-to-hack-someones-account-on-roblox_GM431946152.pdfIn PDF document text
    • https://www.gornjastubica.hr/files/free-coin-coin-master_GM406889139.pdfIn PDF document text
    • https://www.gornjastubica.hr/files/how-to-get-free-skins-in-minecraft_GM479516143.pdfIn PDF document text
    • http://gornjastubica.hr/files/coin-master-free-spin-link-today-2021_GM406889139.pdfIn PDF document text
    • http://gornjastubica.hr/files/are-tiktok-free-views-hack_GM835599320.pdfIn PDF document text
    • https://www.gornjastubica.hr/files/minecraft-toys-for-free_GM479516143.pdfIn PDF document text
    • http://gornjastubica.hr/files/oprewards-free-robux_GM431946152.pdfIn PDF document text
    • https://www.gornjastubica.hr/files/how-do-i-get-free-spins-in-coin-master_GM406889139.pdfIn PDF document text
    • https://www.gornjastubica.hr/files/how-to-get-free-robux-codes_GM431946152.pdfIn PDF document text
    • https://www.gornjastubica.hr/files/free-coin-master-gift-link_GM406889139.pdfIn PDF document text
    • https://www.gornjastubica.hr/files/free-robux-no-human-verification-and-no-survey_GM431946152.pdfIn PDF document text
    • http://gornjastubica.hr/files/coin-master-hack-xyz-download-free_GM406889139.pdfIn PDF document text
    • https://www.gornjastubica.hr/files/how-to-hack-someones-minecraft-account_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
stream_004_off00005397.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x5397 31020 bytes
SHA-256: 7aac9ec1c077cf5510cf2c5d44074e8787b83d74dc65cee5e51226d54d2be0f0
font_01_sfnt_off000098ff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x98FF 18712 bytes
SHA-256: daa6127d12966723f5127b5dc3a4de791d5ae84232722604a7894036431feeec

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