Malicious PDF — malware analysis report

Static analysis result for SHA-256 aab4c935b38539b1…

MALICIOUS

PDF

70.4 KB Created: 2021-09-25 17:47:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: ef3259232c10afb994137b1f451804bc SHA-1: aaa3eb9a38e78bd13e7ed4231031d8dc3fb6376c SHA-256: aab4c935b38539b1b2c7e6f38f6de925abee9277f90ac4de212dd5eef935826b
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to compromised CMS upload directories or disposable hosting, suggesting a link farm designed to distribute malicious content or phish users. The document body is heavily obfuscated and unreadable, providing no direct clues to its intent beyond the presence of these suspicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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 http://deesudcoolingtower.com/userfiles/file/10228987089.pdf In PDF document text
    • https://thic.muki001.com/plugin/ce1/ckfinder/userfiles/files/62969758868.pdfIn PDF document text
    • http://www.ecvbrass.ch/user/web/file/29010249098.pdfIn PDF document text
    • https://www.espymetcalf.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138135460882---27429471229.pdfIn PDF document text
    • http://crocepadrekolbe.it/userfiles/files/xolebawinoralibumu.pdfIn PDF document text
    • http://szyoujin.com/UploadFile/file/20210911190542050.pdfIn PDF document text
    • http://www.caribbeandentist.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613f4c53ad0ab---jebiwalazixezabivi.pdfIn PDF document text
    • https://dakotaterritorydevelopment.com/ckfinder/userfiles/files/vijofase.pdfIn PDF document text
    • http://www.ruben.pl/ckfinder/userfiles/files/21180963955.pdfIn PDF document text
    • http://sanzmendia.com/userfiles/files/punelebalopesilebakukowe.pdfIn PDF document text
    • http://www.alwaysflorida.com/wp-content/plugins/formcraft/file-upload/server/content/files/16141bbea6590e---fijuv.pdfIn PDF document text
    • https://majubesar.com/contents/files/rurosifibuxisemenileki.pdfIn PDF document text
    • https://www.loisirs-auto-occasion.fr/ckfinder/userfiles/files/47375919386.pdfIn PDF document text
    • https://partroyfuneralhome.com/partroy/assets/file/32490311964.pdfIn PDF document text
    • http://luxlustry.ru/img/upload/42991438104.pdfIn PDF document text
    • http://smithmurdock.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130abdd96328---venujejomosozimewa.pdfIn PDF document text
    • https://horgaszvelem.elelmiszer-hazhozszallitas.hu/ckfinder/userfiles/files/lefesipusuwu.pdfIn PDF document text
    • https://atrax.hr/files/memiwem.pdfIn PDF document text
    • https://curewelldiabetes.com/userfiles/file/94354621537.pdfIn PDF document text
    • https://livres-arts.com/ckfinder/userfiles/files/vexuluximupif.pdfIn PDF document text
    • http://www.focitabor.hu/userfiles/file/zikikogibebifedudiloro.pdfIn PDF document text
    • http://de.ruben.pl/ckfinder/userfiles/files/vobamefakofeteg.pdfIn PDF document text
    • http://degeninhotel.ru/admin/ckfinder/userfiles/files/puxofatabusuduf.pdfIn PDF document text
    • http://101-games.ru/images/uploads/files/6817511436.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3vuEKuznOb8/uplcv?utm_term=play+free+online+games+for+android+phonesPDF 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_off0000b35c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB35C 10964 bytes
SHA-256: e769df8488a1762d4461f83ef739a074f589437ebe35d0815eb79fe122134674
font_01_sfnt_off0000cc62.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC62 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e474.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE474 14716 bytes
SHA-256: aef3699dad334827a249c78ccb41283500ca7a9f509f39719532e9e8c9f9c495

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