Malicious PDF — malware analysis report

Static analysis result for SHA-256 8a63681d11a86b58…

MALICIOUS

PDF

117.7 KB Created: 2021-10-09 05:19:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 1d6360366d8e26157ba9cfb64ae0987e SHA-1: b88cfde2de0357cd35d7d6eeab9a0ba545b5cfd9 SHA-256: 8a63681d11a86b5833194a4955e1a67eb51a6652a98cce444fdf6bcfa68a3c24
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Static analysis revealed numerous embedded URLs, many pointing to compromised CMS uploads or disposable domains, characteristic of a link farm used for phishing or malware distribution. The PDF structure and the nature of the URLs suggest it's designed to lure users to external malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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://synerhu.ru/uplcv?utm_term=what+is+reverse+harem PDF link annotation
    • http://aibasavar.edu.bd/app/webroot/ckfinder/userfiles/files/mubuxefel.pdfIn PDF document text
    • http://www.zywawiara.pl/pliki/mujepamobopubapudov.pdfIn PDF document text
    • https://alcc.vn/wp-content/plugins/super-forms/uploads/php/files/ebbla9sh04tgmcets3krvc1k6b/jegezun.pdfIn PDF document text
    • http://rcp-ranstadt.us/files/2639434282.pdfIn PDF document text
    • http://kadh.kr/bobod/upload/file/77526498065.pdfIn PDF document text
    • https://oreopay58.com/ckfinder/userfiles/files/gixulikijateferosimu.pdfIn PDF document text
    • http://queuemanagementsystems.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613a3cb72e477---84114991039.pdfIn PDF document text
    • http://accronline.com/userfiles/file/6644678091.pdfIn PDF document text
    • http://wangguanhardware.com/userfiles/file/80628443277.pdfIn PDF document text
    • http://ipvoicenj.com/wp-content/plugins/formcraft/file-upload/server/content/files/161561f5ab0749---77909375536.pdfIn PDF document text
    • https://abcoegypt.com/userfiles/files/rowetokedikopi.pdfIn PDF document text
    • https://ksuskalology.com/images/file/kidiviwawigezulalafute.pdfIn PDF document text
    • http://psychologadamczak.pl/userfiles/file/50383687766.pdfIn PDF document text
    • https://cgeminfos.ma/upload/file/22042043525.pdfIn PDF document text
    • http://jumpinfit.it/userfiles/files/kamepememetugam.pdfIn PDF document text
    • http://erisalaw-chicago.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/bifuk.pdfIn PDF document text
    • http://vagyonvedelemszolnok.hu/admin/fck_upload/file/54096516291.pdfIn PDF document text
    • http://www.magicapro.it/wp-content/plugins/formcraft/file-upload/server/content/files/1613b785bcb2cb---rixekupapojumuko.pdfIn PDF document text
    • https://www.lavishlook.se/wp-content/plugins/super-forms/uploads/php/files/58ba71d2f928741d08fc7f648ae29315/43396602663.pdfIn PDF document text
    • http://serramentisiciliano.it/userfiles/files/runodosimutotafomedideg.pdfIn PDF document text
    • http://ingfrimale.com/userfiles/files/35170829183.pdfIn PDF document text
    • https://thebottombillion.org/business_school/uploads/file/vukixan.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000160d5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x160D5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000178e7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x178E7 22220 bytes
SHA-256: eb776337c63793723706526d8b0f7bbfc70ed2fe08843aad1d116f96f3ddf561
font_02_sfnt_off0001b2a4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1B2A4 10164 bytes
SHA-256: 7d5b16b4ccbe4fee2570afe05d8e7cb370777262dd9d536115a87b43bddfdc38