Malicious PDF — malware analysis report

Static analysis result for SHA-256 1acb1d8d0071cb6b…

MALICIOUS

PDF

70.2 KB Created: 2021-09-20 21:20:34 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: c81ad41ce839ceb69751304e0586ae00 SHA-1: 5a7886efd1e0fb15d0449ed4005ecaca2353b253 SHA-256: 1acb1d8d0071cb6bc85a99d30f2381b48c47db6bba5b89c4d9ba54d10c51e3ea
156 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Numerous heuristics fired, pointing to the PDF acting as a link farm, directing users to compromised WordPress upload storage and other disposable hosting sites. The embedded URLs, such as 'https://coretry.ru/uplcv?utm_term=android+app+authentication', suggest a phishing or credential harvesting attempt, potentially disguised as an Android app authentication lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9837

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://coretry.ru/uplcv?utm_term=android+app+authentication PDF link annotation
    • http://nova-auto.com/upload/923720389.pdfIn PDF document text
    • https://fultoys.com/userfiles/23694704705.pdfIn PDF document text
    • http://taiwan-tsai.com/upload/files/gafex.pdfIn PDF document text
    • https://www.xcelsus.de/wp-content/plugins/formcraft/file-upload/server/content/files/16148bb58b3574---84872736497.pdfIn PDF document text
    • http://szakkepzosiklos.hu/upload/file/80653318815.pdfIn PDF document text
    • http://studiomistretta.com/userfiles/files/najuwi.pdfIn PDF document text
    • https://xnkvinatimex.com/uploads/files/pewagigub.pdfIn PDF document text
    • http://www.peplex.it/wp-content/plugins/formcraft/file-upload/server/content/files/16133dff9472d2---89559394442.pdfIn PDF document text
    • http://unipell.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16133108b50979---25338079847.pdfIn PDF document text
    • http://s13cf5ef.alojamientovirtual.com/ropadefutbolbarata/userfiles/file/81498405948.pdfIn PDF document text
    • https://toptenstudy.com/upload/files/BodyFile__61376718D1B6D.pdfIn PDF document text
    • http://slowjamsundays.com/wp-content/plugins/formcraft/file-upload/server/content/files/161304c35e83e0---jozabevotivemotel.pdfIn PDF document text
    • https://www.tessilgiada.it/wp-content/plugins/formcraft/file-upload/server/content/files/161437aaab9eae---kajenazosatu.pdfIn PDF document text
    • http://meijialx.com/ckfinder/userfiles/files/27813954343.pdfIn PDF document text
    • http://zavalinka.by/var/upload/file/67864983840.pdfIn PDF document text
    • https://inprovitargentina.com/ckfinder/userfiles/files/kusezudifuwipejevowaweni.pdfIn PDF document text
    • https://shining4u.com/wp-content/plugins/super-forms/uploads/php/files/16ad89eaf031eed3c263ab5037511326/xisiw.pdfIn PDF document text
    • http://ccsctda.com/ckfinder/userfiles/files/20210911_021707.pdfIn PDF document text
    • https://jnvhardoi.org/ckfinder/userfiles/files/nelipikumoraxexisak.pdfIn PDF document text
    • http://agriturismolataggiasca.eu/userfiles/files/mitekuronowavenonegusemo.pdfIn PDF document text
    • http://liderzy.natura2000.pl/imgturysta/files/58714374995.pdfIn PDF document text
    • https://gym-rectif.fr/ckfinder/userfiles/files/bigesefukefur.pdfIn PDF document text
    • http://rdmsrl.it/userfiles/files/nituwo.pdfIn PDF document text
    • http://sevenseahotel.com/uploads/images/files/79944961964.pdfIn PDF document text
    • http://bhttourist.com/upload/fckimagesfile/dubuzozukoxemagiseluw.pdfIn PDF document text
    • https://jotekonybakterium.hu/userfiles/files/8724749158.pdfIn PDF document text
    • http://pokwuttibut.com/file_media/file_image/file/27766253528.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_off0000b566.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB566 10476 bytes
SHA-256: aa3be95e7e491ed0890b23e685c7c97ad57c71a0aaf3c6257e9b12318aa59525
font_01_sfnt_off0000cd24.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD24 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e536.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE536 15132 bytes
SHA-256: b649a71a47245eb9b10f04c5183d5c7617195f8b98ca5bdb29444d6932d3650a

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