Malicious PDF — malware analysis report

Static analysis result for SHA-256 8c71140ec9300f3d…

MALICIOUS

PDF

78.6 KB Created: 2021-09-04 04:51:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 986fb7d9b1ea21c6f9697f63dbdece14 SHA-1: eb27a6759e9cbb9a0f9be023e18ed18f91de9a4b SHA-256: 8c71140ec9300f3d213ba513099f6f5b6023d3c21a46976f29feb90f4cc3c73c
156 Risk Score

Malware Insights

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

The sample is identified as malicious by ML classifiers and ClamAV, specifically as a phishing trojan. It functions as a link farm, embedding numerous URLs that point to various domains, many of which are hosted on compromised CMS platforms or disposable hosting. These links likely serve to redirect users to phishing sites or download further malicious payloads, aligning with spearphishing attachment tactics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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 http://nhasachnguyenvancu.com/Images_upload/files/45052047808.pdf In PDF document text
    • http://morecoredesign.com/images/imageUps/files/lozobonibabavepulibu.pdfIn PDF document text
    • https://technok.cz/wp-content/plugins/super-forms/uploads/php/files/abf7833700c6e7be9f490780fb645a80/memegedinunewiwesivuz.pdfIn PDF document text
    • http://www.logistiekverbeteren.nl/ckfinder/userfiles/files/35834968878.pdfIn PDF document text
    • http://conelser.hu/fck_uploads/file/jegulozurumexufopasab.pdfIn PDF document text
    • http://cbwmd.com/uploads/Files/dapubewesowut.pdfIn PDF document text
    • http://iltorg.ru/upload/file/96606563241.pdfIn PDF document text
    • http://frederickfollows.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16087b061c9f3c---wofimejutovovabojo.pdfIn PDF document text
    • http://wignaccent.com/FCKeditor_2.6.3/userimages/file/20210720183836.pdfIn PDF document text
    • http://smolninskayahotel.com/userfiles/file/zumuvugonava.pdfIn PDF document text
    • https://fenixfalt.com/userfiles/file/1220985477.pdfIn PDF document text
    • http://holdemigny.fr/ckfinder/userfiles/files/79827423341.pdfIn PDF document text
    • http://maxitelt.no/wp-content/plugins/formcraft/file-upload/server/content/files/160b3abf936996---lonatol.pdfIn PDF document text
    • https://fablab808.com/nbloom/fckuploads/file/kodibepofapiro.pdfIn PDF document text
    • http://dok-vo.ru/userfiles/file/88834437979.pdfIn PDF document text
    • http://alpha-th.com/userfiles/file/fakilujodaf.pdfIn PDF document text
    • http://mobitransjogja.com/files/lijadefiwiwosopowijejo.pdfIn PDF document text
    • http://archi1919.com/smlclub-files/file/85788922980.pdfIn PDF document text
    • https://thietbivesinhsonhoa.com/webroot/img/files/38860592925.pdfIn PDF document text
    • http://apluskleaning.com/admin/images/file/vexaparu.pdfIn PDF document text
    • http://prtourusa.com/FileData/ckfinder/files/20210718_11C0DB4F7B76BE24.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/DOqCt-cVA4I/uplcv?utm_term=10th+class+science+book+download+pdfPDF 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_off0000cb05.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB05 18832 bytes
SHA-256: ab35a7c7c9d06b77ac5ce6577759efec2c33ef4500993f3bbc513260f08d9e2a
font_01_sfnt_off0000fbe0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFBE0 11012 bytes
SHA-256: abba63166b27d043b885b3173d4ecef68a9a186b462c91cee1849ec62e1a3501
font_02_sfnt_off00011546.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11546 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1