Malicious PDF — malware analysis report

Static analysis result for SHA-256 c87721b3f27eeeb7…

MALICIOUS

PDF

80.7 KB Created: 2021-07-03 07:04:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 6e1f75f929c505f659f5c5e0e13fb843 SHA-1: b0d00a14a475ee7d280cf028bbaf36268ef93afc SHA-256: c87721b3f27eeeb7b9f762aa96da8965c52eb9407229dff1023d9c762a50844d
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external URLs, many hosted on compromised WordPress sites or disposable domains, suggesting a link farm designed to redirect users. The presence of PDF-specific heuristics like 'PDF_URI' and 'PDF_SEO_DISPOSABLE_LINK_FARM' further supports this, indicating the PDF's primary function is to act as a lure to these external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9972

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 https://synerhu.ru/uplcv?utm_term=shell+shockers+for+ipad PDF link annotation
    • https://its-bulgaria.bg/files/file/sidali.pdfIn PDF document text
    • https://morethancleaningservices.com/wp-content/plugins/super-forms/uploads/php/files/3f53f4e534d0ce5ae1a553645b86c0e7/jadufulamanomasolunaz.pdfIn PDF document text
    • http://hbleg.com/admin/userfiles/files/16109323173.pdfIn PDF document text
    • http://tecresconsolidamentorestauro.it/fck_data/file/siribiligevelobel.pdfIn PDF document text
    • https://daluxerealty.com/wp-content/plugins/super-forms/uploads/php/files/15vs15q0i9tic1g0mqfr6fhtc4/bokogudu.pdfIn PDF document text
    • http://instandee.com/Images_upload/files/9975836991.pdfIn PDF document text
    • https://totalyoumovement.com/wp-content/plugins/formcraft/file-upload/server/content/files/16082104ed6769---59580484717.pdfIn PDF document text
    • http://nek.ua/wp-content/plugins/formcraft/file-upload/server/content/files/16072aa9539301---68082207322.pdfIn PDF document text
    • http://toshiteriyakiburien.com/uploads/files/xibizezaponaxu.pdfIn PDF document text
    • https://www.3dreamchurch.com/wp-content/plugins/super-forms/uploads/php/files/e4f386c9ac469c1e35a15093a8a35e37/voridaxotov.pdfIn PDF document text
    • http://nappsa.org/userfiles/file/gasofukajumonadota.pdfIn PDF document text
    • https://discoverapartmentsforrent.com/wp-content/plugins/super-forms/uploads/php/files/a767fa718aadc67f29a53a0f0e9a0e94/19817980615.pdfIn PDF document text
    • https://actorconseil.com/files/file/leputevav.pdfIn PDF document text
    • https://propbrains.com/wp-content/plugins/super-forms/uploads/php/files/96tm1iesk4c4cr5lr685e81vu7/63497515240.pdfIn PDF document text
    • http://www.argentum.com/wp-content/plugins/super-forms/uploads/php/files/h82opoli5gopnie8atvhu8h3j8/nunejaviw.pdfIn PDF document text
    • https://coachtourbusrental.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607232356b59f---xutavopujit.pdfIn PDF document text
    • https://stonebuild.bg/f/uploads/files/limowozuseduxozaxan.pdfIn PDF document text
    • http://jshtextile.com/UserFiles/file///67885367053.pdfIn PDF document text
    • http://goref.ru/files/file/zujozibovef.pdfIn PDF document text
    • https://supermagnum-bg.com/userfiles/file/sutewolu.pdfIn PDF document text
    • http://argra.rs/wp-content/plugins/formcraft/file-upload/server/content/files/16090daf022c2f---wonibesunexovenoxasa.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_off0000d8dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD8DD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f0ef.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0EF 17132 bytes
SHA-256: 73c607518dd1fccfc79a7f982794219a2798819278ad54c04303931332d05436
font_02_sfnt_off00011d5f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11D5F 10684 bytes
SHA-256: e96b3714ed5acb26816c6d967a1b97b87e1d0653da5b3b1ea5270f78d4d7ea06

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