Malicious PDF — malware analysis report

Static analysis result for SHA-256 677a18f435f1add3…

MALICIOUS

PDF

84.4 KB Created: 2021-08-20 17:37:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: c386438b78a3dcf7b3a3f9ea66aad975 SHA-1: 421422dc98a2d7c3cf0729f3c8384df5b7531546 SHA-256: 677a18f435f1add368c90f2157fb27d90e9b6b8cb4eb44dc080fc6a9f226f2d5
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 of which are hosted on compromised or disposable domains, suggesting a link farm or phishing lure. The presence of PDF-specific heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' further supports this, indicating the PDF is used to redirect users to potentially harmful content. No scripts were extracted, but the overall structure points to a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://philabc.ru/uplcv?utm_term=upstream+intermediate+b2+answers+pdf PDF link annotation
    • http://foto-preiss.at/upload_files/files/41208136498.pdfIn PDF document text
    • https://accesoriosalmayor.com/images/userfiles/file/25979919920.pdfIn PDF document text
    • http://loveperfectionschool.com/upload/file/11075364428.pdfIn PDF document text
    • https://melz-feu.ru/upload/73947522605.pdfIn PDF document text
    • https://nothingbutsafetyglasses.com/userfiles/file/lotisibivugono.pdfIn PDF document text
    • http://cellesekorea.com/ckupload/files/pudixe.pdfIn PDF document text
    • http://drivescuolaguida.it/userfiles/files/jowopixoz.pdfIn PDF document text
    • http://thm-holding.ru/wp-content/plugins/super-forms/uploads/php/files/b85ea5b6fa78de6273f3d3b247f0ccaa/pivoxuzuzuxopixowi.pdfIn PDF document text
    • https://alarouba.com/ckfinder/userfiles/files/80969313419.pdfIn PDF document text
    • https://newat.ru/wp-content/plugins/super-forms/uploads/php/files/76ec937cef8aacd929809474500ead1d/bugog.pdfIn PDF document text
    • http://www.mostenpo.jp/userfiles/files/98814524632.pdfIn PDF document text
    • https://www.ferienhof-schneider.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607437a45c840---mibigoxukasolabexifoxo.pdfIn PDF document text
    • http://allaboutdowney.com/userimages/29779271035.pdfIn PDF document text
    • http://mingmitrcoffee.com/user_img/files/wulifasaratujomuwulabaniv.pdfIn PDF document text
    • https://wagaskar.com/media/97320474732.pdfIn PDF document text
    • https://www.ideaklinikizmir.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607360b411874---80406728282.pdfIn PDF document text
    • https://alihuata.com/userfiles/file/83278924955.pdfIn PDF document text
    • http://holzweiss.at/wawujibufogosudafo.pdfIn PDF document text
    • https://debcopharma.com/userfiles/file/depoxewilumadodazejudet.pdfIn PDF document text
    • https://rzfmuhasebe.com/userfiles/file/zenaxaxo.pdfIn PDF document text
    • https://egyiksem.hu/uploads/file/diwerojana.pdfIn PDF document text
    • http://ecohort.com/userfiles/files/5278603740.pdfIn PDF document text
    • https://kolodezrus.ru/wp-content/plugins/super-forms/uploads/php/files/1179365d5988e1e22534a88dd3b3b7d9/pamexedosina.pdfIn PDF document text
    • https://sandalyecenneti.com/wp-content/plugins/super-forms/uploads/php/files/coqqij72cq3ghmgb7jbda3tuqk/komubumudizuwojonu.pdfIn PDF document text
    • http://studiocariola.com/userfiles/files/8833077907.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_off0000e5bc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE5BC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fdce.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFDCE 17104 bytes
SHA-256: aa7d9d6917f2c958a9c992b162d53a90d8c8242a9974ad8d8d765f49c178d229
font_02_sfnt_off00012aa3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12AA3 10844 bytes
SHA-256: c297e8b61e4cf5c9f36f575b6a9a5c141b7980b6e795d01f9de6f2ad854983ac

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