Malicious PDF — malware analysis report

Static analysis result for SHA-256 5521072c243644f4…

MALICIOUS

PDF

93.6 KB Created: 2021-06-30 12:10:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: 7d9c1d067fdcac8d9d6a6b180f98b4d7 SHA-1: 5d21b6d4b48f1b3967121173ec945645b8e75e47 SHA-256: 5521072c243644f48c1edd83221776c528b21de22b6bc360fe8b3f393cbb560a
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was detected as malicious by ML classifiers and ClamAV, indicating a phishing or trojan threat. It contains numerous links, many pointing to compromised WordPress upload directories, suggesting it's designed to lead users to malicious content or phishing sites. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, further obscuring its true intent beyond being a link farm.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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://infrive.ru/uplcv?utm_term=solving+system+of+linear+equations+using+cramer%27s+rule PDF link annotation
    • https://naoshima-habitant.com/20556155560.pdfIn PDF document text
    • https://medok18.ru/wp-content/plugins/super-forms/uploads/php/files/014036467d2fee636b9c229e4f3c70b0/nobibudu.pdfIn PDF document text
    • https://auf.vn/wp-content/plugins/super-forms/uploads/php/files/b09ss78p7oqu81lff7su1vaao2/7169865941.pdfIn PDF document text
    • https://guclupin.com/calisma2/files/uploads/gopege.pdfIn PDF document text
    • https://segurosjdd.com/wp-content/plugins/super-forms/uploads/php/files/0csifi6rph6382tjrtrjd8i0h6/20485302976.pdfIn PDF document text
    • http://famcareconnect.org/wp-content/plugins/formcraft/file-upload/server/content/files/160985bdbc247f---70152960754.pdfIn PDF document text
    • https://www.cpro.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160768ff20afc8---webonirusulipulevakewexo.pdfIn PDF document text
    • https://www.reparaciondebomba.com.ar/wp-content/plugins/super-forms/uploads/php/files/oocl8acrs81vatat37di7j0k75/63980073820.pdfIn PDF document text
    • http://zhouzhuank.com/v15/Upload/file/20216241515156179.pdfIn PDF document text
    • http://coutleelaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/55886409761.pdfIn PDF document text
    • http://www.thelawchamber.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ab6ee161266---75008634810.pdfIn PDF document text
    • http://vce34.ru/attachments/file/sezibigel.pdfIn PDF document text
    • http://ckpak.com/fckeditor/userfiles/file/sebeke.pdfIn PDF document text
    • http://yilip.net/userData/board/file/palipitel.pdfIn PDF document text
    • https://orldoc.ch/wp-content/plugins/super-forms/uploads/php/files/f703k0epc9v5kmuscs8s16iii3/namerum.pdfIn PDF document text
    • https://forumhotel.by/wp-content/plugins/super-forms/uploads/php/files/s03brujer3bfamd046vbnh5or3/fosesasikex.pdfIn PDF document text
    • http://teplospectr.ru/images/files/82991974619.pdfIn PDF document text
    • http://botosani.ro/img/uploads/file/jilematane.pdfIn PDF document text
    • https://www.alertgy.com/wp-content/plugins/super-forms/uploads/php/files/7b469a93c87b6e069c05f102be361233/63642868589.pdfIn PDF document text
    • https://hgb.se/filer/file/nolizokovos.pdfIn PDF document text
    • https://www.isgs.org/wp-content/plugins/super-forms/uploads/php/files/69ee4fe43eb37b5c50a65c4e75047c06/91338656916.pdfIn PDF document text
    • https://toolsatool.com/userfiles/files/19133754931.pdfIn PDF document text
    • http://voszveszprem.hu/_user/file/xafafimewe.pdfIn PDF document text
    • https://t4g.nasscomfoundation.org/wp-content/plugins/super-forms/uploads/php/files/r0itg3eej3p6eer53ro8dnb5m7/fowupiponagomokawemibiz.pdfIn PDF document text
    • http://braciszewska-klimek.pl/fck_files/file/kalajemutudirofuxosala.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_off000103c9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103C9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00011bdb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11BDB 18440 bytes
SHA-256: ed2ff7d75241ede2cb393a1e61f40d190f94d9a935ffc406ebe0b49cf6a9e84f
font_02_sfnt_off00014c93.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14C93 11212 bytes
SHA-256: fd5a674af482516be6e98c848cf23bd246aa67850818eabcb38a1b43f1e7c37c

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