Malicious PDF — malware analysis report

Static analysis result for SHA-256 c81777e8ae68ae85…

MALICIOUS

PDF

85.2 KB Created: 2021-06-26 23:07:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: a9ff75fead637c212f69858a46a94914 SHA-1: 4a459614132d941823dd4922550e8640f989f627 SHA-256: c81777e8ae68ae858e4bc2a0a927a971fbd18b5e1931fd50f9f64e99763de4d5
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ClamAV as Pdf.Phishing.Trojan and a machine learning classifier. It contains numerous embedded URLs, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a non-clustered link farm on disposable hosting, further supporting a phishing or malware distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9898

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://goldnumber.info/userfiles/file/96375390807.pdf In PDF document text
    • https://www.colegiodesafio.net/home/wp-content/plugins/formcraft/file-upload/server/content/files/160b87847be234---pijep.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d42d0ac9219---88288946832.pdfIn PDF document text
    • http://global-gypsum.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608446bb8585d---vopawazamuwijajivokubigo.pdfIn PDF document text
    • http://esenkardeslerinsaat.com/resimlerfiles/25448020663.pdfIn PDF document text
    • https://duext.com/wp-content/plugins/super-forms/uploads/php/files/4bff63b5e7f74033f4a93a330a5d064a/medopegewawofadonamo.pdfIn PDF document text
    • http://oguzlarotomatiksanziman.com/depo/sayfaresim/file/41720916933.pdfIn PDF document text
    • http://inlikeflintlogistics.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608dcb45319e4---pofusupekivukeze.pdfIn PDF document text
    • http://beetsom.com/PROGRAM_FCKeditor_UserFiles/file/41682987060a242c63c707.pdfIn PDF document text
    • http://palyavalaszto.hu/teszt/upload/file/98574195164.pdfIn PDF document text
    • https://relaxationplusmn.com/wp-content/plugins/super-forms/uploads/php/files/dcea15d880a193955ca325ef586aaa8b/surizaniradi.pdfIn PDF document text
    • http://gd-weimi.com/upfolder/e/files/20210625074924.pdfIn PDF document text
    • https://borderpak.com/wp-content/plugins/super-forms/uploads/php/files/9b8946712739dfc2d08c370dfd6a6342/vakilekujozaxixubixifo.pdfIn PDF document text
    • https://m-co.de/wp-content/plugins/super-forms/uploads/php/files/02o35o914n6lspr21qrtpttd99/18284182101.pdfIn PDF document text
    • http://trendymamy.pl/userfiles/file/dejijisuriwifo.pdfIn PDF document text
    • https://aterhesseg.com/up_image/file/45308551498.pdfIn PDF document text
    • http://sity-luxe.ru/userfiles/file/49772490879.pdfIn PDF document text
    • https://turbooto.vn/upload/files/zetobusofuxomufu.pdfIn PDF document text
    • https://299-45.com/CKEdit/upload/files/lifasisujivewo.pdfIn PDF document text
    • http://nktrading.qa/file/files/2757733491.pdfIn PDF document text
    • http://az4group.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608ada99509e9---vanenujomom.pdfIn PDF document text
    • https://zweiund40.com/wp-content/plugins/super-forms/uploads/php/files/vb77bb1coqg5a2h4ql84d2gd8k/zezewikededozekolitapipen.pdfIn PDF document text
    • http://www.virtualaid.eu/wp-content/plugins/formcraft/file-upload/server/content/files/1607022012b3d2---63442026533.pdfIn PDF document text
    • https://www.reflectionuk.com/wp-content/plugins/super-forms/uploads/php/files/sjb4dfrfhr68j4cl0ih38cnrl7/54414582402.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=what+does+a+herniated+disc+feel+like+in+middle+backPDF 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://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_off0000efda.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFDA 16536 bytes
SHA-256: 9b0dac06e66bd22f8dfb9bfceea607c84851575210a69f960eb5506a7a3efdd7
font_01_sfnt_off00011a89.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A89 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000132a0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x132A0 10964 bytes
SHA-256: 527ffe1bb33ce5adbdebacaeb39bc251145e66812cbb57535b77c3b9d252c060

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