Malicious PDF — malware analysis report

Static analysis result for SHA-256 73dc16814780c316…

MALICIOUS

PDF

81.6 KB Created: 2021-09-19 22:07:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 8e49f23b0f16146d481ea90d213cbf10 SHA-1: 3fa989a47af13f33a2860f02590712931df0682d SHA-256: 73dc16814780c3165129b2d6c3a9d17f5e45e602093c92cfd589bf58e1ebde9b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by multiple heuristics as containing a link farm and was detected as malicious by ClamAV and an ML classifier. The embedded URLs, such as 'https://cructi.ru/uplcv?utm_term=lg+vs+samsung+phone+quality' and 'http://baharemadinah.com/wp-content/plugins/formcraft/file-upload/server/content/files/16141ed856e89a---xinimisokofewoxagupusijar.pdf', suggest a phishing or malware distribution attempt. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, indicating it's not intended for direct user reading but rather to host these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://cructi.ru/uplcv?utm_term=lg+vs+samsung+phone+quality PDF link annotation
    • https://firsatoyun.com/calisma2/files/uploads/65683790974.pdfIn PDF document text
    • https://kompaspt1.com/contents/files/3962626524.pdfIn PDF document text
    • http://kool-house.com/upload/editor/file/risuz.pdfIn PDF document text
    • https://immo-cjeanpaul.lu/userfiles/files/96982570691.pdfIn PDF document text
    • https://eclipsetheaters.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f8ebd4d882---47905482512.pdfIn PDF document text
    • http://thaymanhinhlaptop.com/userfiles/file/fosisi.pdfIn PDF document text
    • http://aatmicscience.org/asuserfiles/file/supex.pdfIn PDF document text
    • http://teakdeck.pl/files/file/nujegux.pdfIn PDF document text
    • https://ratodua.com/contents/files/zinarabawenimamiteloxaj.pdfIn PDF document text
    • http://www.advancedevents.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1613f51a37fa60---95484522048.pdfIn PDF document text
    • http://www.shjkyq.com/up_files/FCK/file/gususaxafafijumex.pdfIn PDF document text
    • http://hzeiger.com/userfiles/file/72754556740.pdfIn PDF document text
    • http://energywork.pl/userfiles/file/67405716267.pdfIn PDF document text
    • https://prawobrzeze.info/userfiles/file/pedufaraj.pdfIn PDF document text
    • https://fpcofmacon.com/nbloom/fckuploads/file/wodivokubotedizidutewa.pdfIn PDF document text
    • https://dmitrovka-zn.ru/admin/ckfinder/userfiles/files/37528794001.pdfIn PDF document text
    • https://www.birdandwildlifeteam.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613f2ee2082f5---26224085149.pdfIn PDF document text
    • http://townofwinslowin.com/flash/townofwinslowin.com/file/52499811578.pdfIn PDF document text
    • http://pomelieagency.com/userfiles/files/37183399703.pdfIn PDF document text
    • http://baharemadinah.com/wp-content/plugins/formcraft/file-upload/server/content/files/16141ed856e89a---xinimisokofewoxagupusijar.pdfIn PDF document text
    • https://aannemingsbedrijfbarthulsbosch.nl/userfiles/file/84180512366.pdfIn PDF document text
    • http://www.polni.si/Images/files/wizakavujijotozutefimur.pdfIn PDF document text
    • http://thankschicken.com/uploads/files/50955472846.pdfIn PDF document text
    • http://bluebossa.pl/files/file/xodefepofu.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_off0000d9c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9C4 10980 bytes
SHA-256: 76df3a6ffca05d5d9e9e7cee3459aa16594f69450dddb6cbbe30e1501d029b0d
font_01_sfnt_off0000f2c3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2C3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010ad5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10AD5 17716 bytes
SHA-256: 098673e90a3cf31b7558fc93eb11a2666ef80b095f164a264272678844459ce5

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