Malicious PDF — malware analysis report

Static analysis result for SHA-256 28d3a36e0703aa91…

MALICIOUS

PDF

71.6 KB Created: 2021-06-25 16:08:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-25
MD5: a4f6c33113753f1723524a060b685a4b SHA-1: 65095721e542a3d6eb97a0dd575233dba9b5be15 SHA-256: 28d3a36e0703aa916b46d17189befd62d555f00c64c74c2babcb3317dd64c4d2
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous links, many pointing to compromised CMS uploads and link farms, designed to redirect users to potentially harmful websites under the guise of a PDF to Word conversion tool. While no scripts were explicitly extracted, the PDF structure and embedded links strongly suggest a phishing or redirection attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

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://www.siemers-deutschmann.de/wp-content/plugins/super-forms/uploads/php/files/cacd25sfn95gsupr1jdk4upi7g/ravoxulajakajivatuvimax.pdf In PDF document text
    • http://drvision.org/wp-content/plugins/formcraft/file-upload/server/content/files/160d5bad5064a8---33905151698.pdfIn PDF document text
    • http://cuanhuaabshanquoc.vn/files/85263385140.pdfIn PDF document text
    • http://www.gradur.ba/wp-content/plugins/formcraft/file-upload/server/content/files/160ab5169f1c92---23647717837.pdfIn PDF document text
    • http://4grd.com/cmsimages/file/zolozutom.pdfIn PDF document text
    • http://www.gunyagder.org.tr/wp-content/plugins/super-forms/uploads/php/files/o9dvom1rbk0qnuu0ovfq7ed0a3/88874258469.pdfIn PDF document text
    • https://spencershaulageltd.co.uk/wp-content/plugins/super-forms/uploads/php/files/e38f9e7bdffaf072fa17a8163f2a06d7/fafem.pdfIn PDF document text
    • https://pluckywize.com/wp-content/plugins/formcraft/file-upload/server/content/files/16071cc835ec80---91316984652.pdfIn PDF document text
    • https://wholisticvibrations.com/wp-content/plugins/super-forms/uploads/php/files/4fcf14a7965aa8eae8943b5cf559d598/bunimufibufesefiwos.pdfIn PDF document text
    • https://selectwifi.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bc6d5030bc4---67227962193.pdfIn PDF document text
    • https://championsforchildren.org/wp-content/plugins/super-forms/uploads/php/files/732075014ce1b67bb981b52247c5ac1a/jigewegubazew.pdfIn PDF document text
    • http://grani-tonkogo-mira.ru/wp-content/plugins/super-forms/uploads/php/files/f1b73dc464630ad40484fed672f305dc/wejorukutigegozezuf.pdfIn PDF document text
    • http://luckyassessoria.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1606cf1b23c34a---85600952693.pdfIn PDF document text
    • http://bsp-oblspl.org/ckfinder/userfiles/files/39326289284.pdfIn PDF document text
    • http://gezond-trakteren.nl/kasteel-doornenburg-img/bestandenfile/33395823180.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/6naE_Nh8_CY/uplcv?utm_term=convert+pdf+to+word+stepsPDF 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_off0000b867.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB867 10376 bytes
SHA-256: 5733e90f690337c29a2111dea97142e1abd0e834eff93cede6c6e0f4fa42d0a6
font_01_sfnt_off0000d013.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD013 16108 bytes
SHA-256: ee0dc97ac114137e6bd6f826c801bf1c02aad02316ce038a1b11f68cf00648f4
font_02_sfnt_off0000f9e0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9E0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1