Malicious PDF — malware analysis report

Static analysis result for SHA-256 b5d8c4c59dfe33e0…

MALICIOUS

PDF

86.7 KB Created: 2021-09-20 01:23:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: a1dfdc95864dcf7f756cd5443739cc12 SHA-1: 739a6193f3747cf0653a37e97941392b904503a7 SHA-256: b5d8c4c59dfe33e02e9a2e21ceaef110930879ec8ea2b6ea41dd46b3c6eee2c3
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple external URLs, some hosted on compromised WordPress sites. 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 0.9948

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://archism.ru/uplcv?utm_term=bluetooth+android+to+pc PDF link annotation
    • http://premiumdrinks.eu/userfiles/xerelokulegev.pdfIn PDF document text
    • http://sunway.me/uploads/file/132015562887.pdfIn PDF document text
    • http://tradotel-riviera.com/file/26332883685.pdfIn PDF document text
    • https://danielfelber.ch/userfiles/file/43593436955.pdfIn PDF document text
    • http://lovec.bg/root/ckfinder/userfiles/files/bomatejixekeridisata.pdfIn PDF document text
    • http://www.slappedtogether.com/editoruploadfiles/file/rogivokunofipodejudoja.pdfIn PDF document text
    • http://www.fullertherapy.com/wp-content/plugins/formcraft/file-upload/server/content/files/161439eccb5649---232292803.pdfIn PDF document text
    • https://whiteplacard.com/UserFiles/file/81805171856.pdfIn PDF document text
    • https://serihosting.com/calisma2/files/uploads/rolunogofogejufugavix.pdfIn PDF document text
    • http://insightonafrica.in/userfiles/file/rojusi.pdfIn PDF document text
    • http://ttlengenharia.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613f258b12f37---ropejok.pdfIn PDF document text
    • https://pikewallis.no/wp-content/plugins/formcraft/file-upload/server/content/files/1613f7c4e1a5a5---pelop.pdfIn PDF document text
    • http://rigosarchitects.gr/userfiles/file/93298873280.pdfIn PDF document text
    • http://actionelectric.pt/www/wp-content/plugins/formcraft/file-upload/server/content/files/16142bb09c88fd---60497369414.pdfIn PDF document text
    • http://aktien-analyse.de/images/File/85703798194.pdfIn PDF document text
    • http://flapboxes.com/userfiles/files/67053152993.pdfIn PDF document text
    • http://remontnoedelo.ru/wp-content/plugins/formcraft/file-upload/server/content/files/161473879bce78---38089527988.pdfIn PDF document text
    • https://atasuorganiktarim.com/upload/ckfinder/files/ladasamefovukibifo.pdfIn PDF document text
    • https://safarekhoob.ir/basefile/safarekhoobir/files/posuvalojomo.pdfIn PDF document text
    • https://triangle-electronics.com/assets/userfiles/file/70830940016.pdfIn PDF document text
    • http://zabradli-znerezu.cz/userfiles/file/1302187475.pdfIn PDF document text
    • http://thepducphat.com/upload/files/lugitor.pdfIn PDF document text
    • http://granitemountainranch.net/userimages/58884745043.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_off0000ee19.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE19 18304 bytes
SHA-256: 22b316993224d2f00e3b6aa6f580373643bec8284a39818477b4a24c90eeaa29
font_01_sfnt_off00011db7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11DB7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000135ce.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x135CE 10596 bytes
SHA-256: 5b1b0d9594a3aa20d43ef621e581550eb4368b9ae7d997984bbe35a65e27018c

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