Malicious PDF — malware analysis report

Static analysis result for SHA-256 71838e77e6e2ef4c…

MALICIOUS

PDF

82.9 KB Created: 2021-09-18 22:59:34 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 80f7ec37394fb3e8634bb6fa93d2e041 SHA-1: e62337a51b33d0a3c3187ccbb10040753b0c57dc SHA-256: 71838e77e6e2ef4c9ae3e39de537ebb9d40453b1e37da1c644794ba6f1fa5fb3
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous URLs pointing to compromised or disposable domains, suggesting an attempt to lure users to malicious sites. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but likely serving as a container for the malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

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://saikekanglun.com/filespath/files/20210917213150.pdf In PDF document text
    • https://lescourailleurs.com/upload/editor/file/27400685247.pdfIn PDF document text
    • https://ewastexperts.com/userfiles/files/nexiwawapivelibe.pdfIn PDF document text
    • http://managhantasala.net/mailuserfiles/file/97231291456.pdfIn PDF document text
    • http://sspvjd.com/FileData/ckfinder/files/20210903_63D74F7BDA483224.pdfIn PDF document text
    • https://trompis-tondschungel.de/userfiles/file/82256499832.pdfIn PDF document text
    • https://tecsal.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613c3a8a54721---31652592871.pdfIn PDF document text
    • http://4els.ru/uploads/images/files/pirudovuvosiwawujeme.pdfIn PDF document text
    • http://swotaweb.com/img/upload/file/xugejosapokudovetovelozow.pdfIn PDF document text
    • https://fmpride.com/wp-content/plugins/super-forms/uploads/php/files/1e978a69fe960b5818004bbf7924ca4a/suxumutozexafovumi.pdfIn PDF document text
    • http://asesorialuishervas.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137748b9e3c5---mexonesadesadom.pdfIn PDF document text
    • http://osteriailgalloelinnamorata.com/userfiles/files/54344374377.pdfIn PDF document text
    • http://thegioicamdo.com/upload/files/wewinu.pdfIn PDF document text
    • http://xsteelstock.com/d/files/zewixiguvok.pdfIn PDF document text
    • http://tcsklife.com/filespath/files/20210909190859.pdfIn PDF document text
    • http://phantasos.org/userfiles/file/91166259851.pdfIn PDF document text
    • http://sitarofindiamd.com/userfiles/file/53176596115.pdfIn PDF document text
    • http://www.tiande-global.com/ckfinder/userfiles/files/68279750011.pdfIn PDF document text
    • http://slowjamsundays.com/wp-content/plugins/formcraft/file-upload/server/content/files/16136cb98a3e1b---16855680267.pdfIn PDF document text
    • https://renfrewareahealthvillage.ca/ckfinder/userfiles/files/pufome.pdfIn PDF document text
    • https://srilangkapools.com/contents/files/jarowidaf.pdfIn PDF document text
    • https://ktmcollege.org/public_html/userfiles/file/69287078828.pdfIn PDF document text
    • https://bestmiamiturf.com/wp-content/plugins/super-forms/uploads/php/files/e4824133e1cd68c3d1da2bbfcab60f74/ranira.pdfIn PDF document text
    • http://smsgurugram.com/miet/assets/files/64555475947.pdfIn PDF document text
    • http://szjg.hu/images/file/23326416228.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=the+bachelor+free+streamPDF 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_off0000dfc3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFC3 17572 bytes
SHA-256: c95279abfd0489f346d3d035e5d4595272c40c5c423bfe55a3d521b1fc726f35
font_01_sfnt_off00010dac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10DAC 10508 bytes
SHA-256: 37053cc6b705dcc74bf3204f0849134ce1f8184e1f50c07e5e1df94145f539e8
font_02_sfnt_off000125ac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x125AC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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