Malicious PDF — malware analysis report

Static analysis result for SHA-256 c88fa8168e1ec480…

MALICIOUS

PDF

71.4 KB Created: 2021-09-17 12:20:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 5020c6556c5c62d20904e148e69eca2e SHA-1: 7f7be97b46847b708a4187c010752d2305a6fa48 SHA-256: c88fa8168e1ec480cf175edc6a9ce2891fec1910519960947b1405bc582acdcb
156 Risk Score

Malware Insights

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

The PDF contains numerous links to external PDF files, many hosted on domains associated with compromised CMS uploads or disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or distributing further malware. No scripts were extracted, and the document body was unreadable, but the heuristic firings and URL analysis are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 http://cissi.it/userfiles/files/6173131829.pdf In PDF document text
    • http://rockhousemethod.com/ckfinder/userfiles/files/dizekuj.pdfIn PDF document text
    • http://sanyosushiglendora.com/uploads/files/94179709242.pdfIn PDF document text
    • http://biosystech.com/pdsFck/file/fosidigez.pdfIn PDF document text
    • http://creativetechno.in/userfiles/file/serapepokovapeneleviv.pdfIn PDF document text
    • http://proxkimya.com/resimler/files/69233282326.pdfIn PDF document text
    • http://stphilomenaonline.org/userfiles/file/tulupezexategufa.pdfIn PDF document text
    • http://2017.letnifestiwal.pl/ckfinder/userfiles/files/71583986159.pdfIn PDF document text
    • http://gloteckr.com/upload/editor/file/67965080373.pdfIn PDF document text
    • http://plncse.hu/php_data/file/weguxawezodategifuzelur.pdfIn PDF document text
    • http://jcpingie.be/public/files/wulodeberibogogojekariso.pdfIn PDF document text
    • http://kusistoconstruction.com/userfiles/file/82791217868.pdfIn PDF document text
    • http://www.radio-kum.si/data/files/5956964995.pdfIn PDF document text
    • http://brette-animation.com/userfiles/file/98870366426.pdfIn PDF document text
    • http://cameronhaddock.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614098d6c01a3---jajepofibidekisujuvebebos.pdfIn PDF document text
    • http://alvit-bk.ru/userfiles/file/65618252108.pdfIn PDF document text
    • http://poddertradingandindustries.com/userfiles/file/bonamefimadimikezulugas.pdfIn PDF document text
    • http://market-oborudovanie.ru/upload/file/pilowesisixivu.pdfIn PDF document text
    • http://kaplanpm.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e52a7f3c85---risekoseninobina.pdfIn PDF document text
    • https://mikepromedia.com/wp-content/plugins/super-forms/uploads/php/files/061ba32c0c38a7bd6b3cbd06241ac0a5/tapowonofaraga.pdfIn PDF document text
    • https://pasarangroup2.com/contents/files/85315015177.pdfIn PDF document text
    • https://firesystem.ro/imagini_ws/43750976963.pdfIn PDF document text
    • https://www.mobytec.com.br/mobytec/wp-content/plugins/formcraft/file-upload/server/content/files/16143ec18e82ca---wisadefedixevewitijasibu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=8+bit+farm+apkPDF link annotation
    • 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_off0000b8b9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB8B9 10292 bytes
SHA-256: 4e1b624a4c35a5ceba660a439ba867d12becaaf7af3dee71ebfbc9f8c08b8369
font_01_sfnt_off0000cfa7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCFA7 16012 bytes
SHA-256: ceeaeca95904ee3e5b33a3b6cfb88a7fcfab3dadc9270213e5f656c9888ac0b8
font_02_sfnt_off0000f861.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF861 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1