Malicious PDF — malware analysis report

Static analysis result for SHA-256 a31378b355ae852c…

MALICIOUS

PDF

69.0 KB Created: 2021-09-25 06:18:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: f0868e5e93d4f85dd122c16ebe5622b8 SHA-1: 83a92def112ee50e35b90a2cc231485e582cfdb3 SHA-256: a31378b355ae852cc2ae16c89ee1fbbcf66c7b513fc0111ed4c396a326faf02c
184 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF document is identified as malicious by multiple heuristics and a machine learning classifier, with ClamAV detecting it as a phishing trojan. It employs an image-only lure, typical of phishing, to obscure clickable links. The embedded JavaScript and numerous external URIs point to compromised WordPress uploads and disposable hosting, indicating a phishing campaign designed to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

Heuristics 8

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Image-only document with action trigger (screenshot lure) medium PDF_IMAGE_LURE
    PDF has 1 image(s), only 0 text block(s), carries a click-outward action, and is only 68 KB — typical shape of a phishing lure where a full-page screenshot hides a clickable button that launches or submits to an attacker URL.
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://ketchas.ru/uplcv?utm_term=upper+intermediate+reading+exercises+pdf PDF link annotation
    • http://vollaracis.com/UserFiles/file/17744567909.pdfIn PDF document text
    • https://mayersoffice.com/userfiles/file/5937728774.pdfIn PDF document text
    • http://lynxauto.ru/userfiles/file/27558838757.pdfIn PDF document text
    • https://gauravkankariya.com/wp-content/plugins/super-forms/uploads/php/files/64178a4b89ca2250b76009f3766b4ca1/bobifoduxanile.pdfIn PDF document text
    • http://sql110.com/pic/76687304590.pdfIn PDF document text
    • http://shinaval.ru/userfiles/file/49281069035.pdfIn PDF document text
    • http://www.ashtralmedia.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d2a299d2fe---14712485082.pdfIn PDF document text
    • http://konakelektrik.com/userfiles/file/68671720871.pdfIn PDF document text
    • http://wwm-quanta.com/upload/files/84503179798.pdfIn PDF document text
    • http://khonggianmang.com/upload/files/5210485036.pdfIn PDF document text
    • https://horgaszvelem.hu/ckfinder/userfiles/files/pefazananipiranu.pdfIn PDF document text
    • http://mprime.net/ckfinder/userfiles/files/26263991858.pdfIn PDF document text
    • http://rebornfair.com/FileData/ckfinder/files/20210923_3196C8CF02939FAB.pdfIn PDF document text
    • http://dishandspoonproductions.com/ckfinder/userfiles/files/18282592512.pdfIn PDF document text
    • http://www.investing-in-women.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614e57240538d---latatonikuxukaj.pdfIn PDF document text
    • https://www.colegiodomus.com.br/js/ckfinder/userfiles/files/ruponawujosulirul.pdfIn PDF document text
    • http://castudio.eu/userfiles/files/zujivizoxofopananani.pdfIn PDF document text
    • https://ist-lb1.istanajp.com/contents/files/vavepefawat.pdfIn PDF document text
    • http://weldingplaza.com/files/file/sozogurakawikul.pdfIn PDF document text
    • https://magic-ray.shop/uploads/files/xekatotakamufasotozob.pdfIn PDF document text
    • https://homestayhoian.vn/uploads/image/files/74982274278.pdfIn PDF document text
    • http://retailcop.ca/files/xasibagojoboteninirawifek.pdfIn PDF document text
    • https://warungmimpishio2.com/contents/files/74035228283.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_off0000b11f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB11F 10904 bytes
SHA-256: fddf5526e5f32798c0bef6d680cb3b3355e1f253a3f0cb8aa501462c41770d47
font_01_sfnt_off0000ca23.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA23 14264 bytes
SHA-256: 6866005f668b1c0864fb85887edda12585b7c774ff6cfd7f8da116f8e095ae38
font_02_sfnt_off0000ee0b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE0B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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