Malicious PDF — malware analysis report

Static analysis result for SHA-256 a15de21d65f92d75…

MALICIOUS

PDF

79.9 KB Created: 2021-09-11 14:33:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-07
MD5: 868cc6d032596232c9d399f427468c32 SHA-1: 378dd296de5ed11b007690faec23f1ff07972be4 SHA-256: a15de21d65f92d756aca375fa79097097c3565b1388113b20fcfe599dc3c2f05
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and a machine learning classifier indicated a high probability of maliciousness. Heuristics identified it as a link farm, with many embedded URLs pointing to potentially compromised or disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://marksiegeldds.com/wp-content/plugins/super-forms/uploads/php/files/2fc0fd80142adfdd8ecf744fb5abe3d1/90378495326.pdf In PDF document text
    • http://studiosantese.eu/userfiles/files/21907076582.pdfIn PDF document text
    • http://ryanoomen.nl/uploadimages/files/pubonodok.pdfIn PDF document text
    • http://fratellilongoni.com/userfiles/files/rawixutubuxokugagitok.pdfIn PDF document text
    • http://xn--80aikni6a0b.xn--p1ai/images/file/58208788003.pdfIn PDF document text
    • http://ersenergy.com/UserFiles/file/dilodivozimosigus.pdfIn PDF document text
    • http://mptech.vn/ckfinder/userfiles/files/36901159585.pdfIn PDF document text
    • https://www.advids.co/wp-content/plugins/formcraft/file-upload/server/content/files/161331f552d99a---rurafum.pdfIn PDF document text
    • http://pantryscan.com/123cars/imagefck/file/jiminemurubekuguvex.pdfIn PDF document text
    • http://araulmor.tel-cor.com/images/library/file/mexofexoxopurinenefo.pdfIn PDF document text
    • http://kerekesvillszer.hu/UserFiles/file/sekirumeraruniseza.pdfIn PDF document text
    • https://tasteadmin.com/ckfinder/core/connector/php/custom/wysi_uploads/files/52548810950.pdfIn PDF document text
    • http://kibunajcc.com/ckfinder/userfiles/files/wenewim.pdfIn PDF document text
    • https://nusamulticentralestari.com/Uploads/userfiles/files/71550908808.pdfIn PDF document text
    • http://thuonghieutoancau.vn/uploads/files/49750849290.pdfIn PDF document text
    • https://bednidhitraders.com/userfiles/file/1325584232.pdfIn PDF document text
    • http://nwatchonline.org/userfiles/file/mosasak.pdfIn PDF document text
    • https://fulzugaskozpont.hu/files/82529037011.pdfIn PDF document text
    • https://provisionsinternational.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613046a71f488---dadome.pdfIn PDF document text
    • http://csc0851.com/userfiles/file/20210904190829_a8dgpn.pdfIn PDF document text
    • http://ksnjl.com/userfiles/files/figemejivikasodumisoj.pdfIn PDF document text
    • https://asztromiskolc.hu/ckfinder/userfiles/files/73833379965.pdfIn PDF document text
    • http://onlinecommerce.bg/uploads/pages/files/goniwodi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=how+to+block+messages+from+truecallerPDF 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_off0000d0f9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD0F9 10892 bytes
SHA-256: 4ca21c9892ff74690f5e9f0977ae32bdc2385237c5c1fc789547fab3d9d48329
font_01_sfnt_off0000ea56.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA56 18256 bytes
SHA-256: d0d42623b41cb1cd2954655610a4b7ae510431cffdd5727c52e09ae62c9a138d
font_02_sfnt_off0001197d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1197D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1