Malicious PDF — malware analysis report

Static analysis result for SHA-256 79eb4d0c2dc551b9…

MALICIOUS

PDF

93.2 KB Created: 2021-09-23 18:26:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 0b066db98ece37d1e276412799b8c946 SHA-1: 47f564ebd209f97f43e6218b0fd4ccc8f156236f SHA-256: 79eb4d0c2dc551b9fb279583238b3fd03a849afb91d14a234beae685992b0e45
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected by ClamAV as Pdf.Phishing.Trojan and an ML classifier flagged it with high confidence. It contains numerous external links, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users. The presence of PDF_URI and PDF_SEO_DISPOSABLE_LINK_FARM heuristics indicates a pattern of redirecting users to potentially malicious external content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://coretry.ru/uplcv?utm_term=the+worm+ouroboros+pdf PDF link annotation
    • http://www.xn----9sbkvfu2aex3d.xn--p1ai/ckfinder/userfiles/files/texapufita.pdfIn PDF document text
    • http://qhchemicalsfeed.com/upload/files/71046621915.pdfIn PDF document text
    • http://parkwestresidences.com/wp-content/plugins/formcraft/file-upload/server/content/files/161437f070e9b4---40648771675.pdfIn PDF document text
    • https://vhcvietnam.vn/ckeditor/images/files/74215330698.pdfIn PDF document text
    • https://bruceleevideos.org/images/file/56459896469.pdfIn PDF document text
    • http://area100impianti.it/userfiles/files/55943901614.pdfIn PDF document text
    • http://roomyab.ir/basefile/roomyabir/files/figozokorase.pdfIn PDF document text
    • http://pass38.com/images/contentimages/files/wukisi.pdfIn PDF document text
    • https://studiecarriere.it/uploads/file/kojotuvowurokaviwed.pdfIn PDF document text
    • https://zippy-inc.com/app/webroot/userfiles/files/20141071295.pdfIn PDF document text
    • http://lixupeng.com/uploads/files/dukedafasegesoxofobafugij.pdfIn PDF document text
    • http://nanobubblevietnam.com/uploads/userfiles/file/sudabowodakazuwekogovibu.pdfIn PDF document text
    • http://le-lemniscus-incandescent.fr/ckeditor/upload/files/zevufepefojumukoxona.pdfIn PDF document text
    • https://www.horisunmauritius.com/wp-content/plugins/super-forms/uploads/php/files/05a5187f8a7d5df0a37b9ade67910e64/zuvamir.pdfIn PDF document text
    • http://zpkprzemysl.pl/ckfinder/userfiles/files/tawerarusewawudoz.pdfIn PDF document text
    • http://kpghomerepairs.com/uploads/image/files/finorafabaxidivetof.pdfIn PDF document text
    • https://xn--1--8kcai1ck2bs.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/e7e1ab1d250d81d2c7c580f23fe00488/43626992731.pdfIn PDF document text
    • http://jplus-ag.com/upload/files/BodyFile__6130300CAA3E2.pdfIn PDF document text
    • http://about-dogs.ru/upload/file/28892929251.pdfIn PDF document text
    • http://indagosrl.it/userfiles/files/6266383752.pdfIn PDF document text
    • http://geometracosentino.com/userfiles/files/nemuzega.pdfIn PDF document text
    • https://nazragame.com/calisma2/files/uploads/96962585898.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_off00010630.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10630 18784 bytes
SHA-256: ad7a0d0544e2bb8807a1c6921ba9c6af1a7ad11c127437b9de0986145a91332d
font_01_sfnt_off00013753.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13753 10548 bytes
SHA-256: d53c9aa207ef8e7df1cbc00d455a8cf2817b973f1b612a71e5fe3d7c01d8b944
font_02_sfnt_off00014f37.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14F37 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1