Malicious PDF — malware analysis report

Static analysis result for SHA-256 873615a139a2fddf…

MALICIOUS

PDF

86.6 KB Created: 2021-07-08 10:16:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: 0fba4f8bb34e4df7072fea1774abd3d2 SHA-1: 610a06ce1069185c86b9cbc192beac47a9f48eeb SHA-256: 873615a139a2fddf4fda2abfb494c53bb6cc0ebc230496d18b418361390c3f19
196 Risk Score

Malware Insights

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

The sample is a PDF document that contains numerous links pointing to external resources. Several heuristics indicate that these links are part of a link farm hosted on compromised WordPress sites and disposable domains, likely intended to distribute malware. The ML classifier and ClamAV detection strongly suggest malicious intent, classifying it as a phishing trojan.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://pnp-studio.com/fckeditorfiles/file/boxojup.pdf In PDF document text
    • http://dekoblickfang.de/userfiles/file/mibaxegerulugosatakutowa.pdfIn PDF document text
    • https://www.hauptsache.cc/wp-content/plugins/formcraft/file-upload/server/content/files/1608bf8eeb7227---podalukegerapenomakoso.pdfIn PDF document text
    • http://suportti.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609158c46deb7---58764993841.pdfIn PDF document text
    • https://levin-dent.ru/wp-content/plugins/super-forms/uploads/php/files/8edc3783b014fd80468a787de903109d/74841317203.pdfIn PDF document text
    • http://www.akutrans.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d636d2677ba---putuvinalo.pdfIn PDF document text
    • https://dezsredstvompx.ru/wp-content/plugins/super-forms/uploads/php/files/51abfdd4ebc4ae26e198e758e60275e6/lonokikuserozo.pdfIn PDF document text
    • http://tokyoracing.hu/userfiles/file/surupewonizasazuvukonipap.pdfIn PDF document text
    • http://files.ibiza-ferien.de/file/29182210635.pdfIn PDF document text
    • http://angerdress.store/ckfinder/userfiles/files/89221608276.pdfIn PDF document text
    • http://studiotecnicomancini.eu/userfiles/files/47001813954.pdfIn PDF document text
    • https://www.landalastadservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606ccafc4fa72---nifuzuji.pdfIn PDF document text
    • http://cy2hand.com/userfiles/63482815328.pdfIn PDF document text
    • https://www.blackandwhite-salon.com/wp-content/plugins/super-forms/uploads/php/files/378d9c2e608ae2e37e80e9cfcb07321b/sijijuwiji.pdfIn PDF document text
    • http://ccshecea.org/upload/files/farumisovuvolewagosuv.pdfIn PDF document text
    • https://rosemonttherapy.health/wp-content/plugins/super-forms/uploads/php/files/75b2l2m4m502jv9v83bhm54en7/likotijaxomo.pdfIn PDF document text
    • http://iideree.org/wp-content/plugins/formcraft/file-upload/server/content/files/1607149684a644---janufinuxexekaxumavugole.pdfIn PDF document text
    • https://astefin.ro/ckfinder/userfiles/files/nezozol.pdfIn PDF document text
    • http://for-rent-aalst.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609d0e739c0e5---25907866854.pdfIn PDF document text
    • http://harlit.com/ckfinder/userfiles/files/20210703_194338.pdfIn PDF document text
    • http://www.dnevi-sekretarjev.eu/wp-content/plugins/formcraft/file-upload/server/content/files/16099b58a608ea---vidafokulibuge.pdfIn PDF document text
    • http://artistalexanderkanevskywinnerinternationalaward.com/clientMedia/file/50625989916.pdfIn PDF document text
    • http://hillcountryawningsandsunscreens.com/wp-content/plugins/formcraft/file-upload/server/content/files/16075c73557098---davidiluwade.pdfIn PDF document text
    • http://sad-azov.ru/wp-content/plugins/super-forms/uploads/php/files/335a205555c2a30d3d23b9edf61bf03b/rolinew.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3vuEKuznOb8/uplcv?utm_term=ohs+act+2007PDF 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_off0000f243.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF243 10048 bytes
SHA-256: a8e92f5907875bb8e04befa485c18c0db04da1d7e8b1e09644b36c1331c34a81
font_01_sfnt_off000108ea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x108EA 17004 bytes
SHA-256: 9b36cd9dff0ab292d229361c011cd3803644e0364f9e4830a4ad45dd2406a25f
font_02_sfnt_off00013592.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13592 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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