Malicious PDF — malware analysis report

Static analysis result for SHA-256 a6dc74c9a80415e8…

MALICIOUS

PDF

82.6 KB Created: 2021-09-19 11:26:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 87c4cd0aeb0f9136dd3cca72064d1482 SHA-1: cbe60bda369c31bf6099f00cb0d10abd77013afd SHA-256: a6dc74c9a80415e89be66649a082e0bf5e67976e1a67144cb70e4c1d2d0d98bb
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, many of which point to PDF files hosted on various domains, suggesting a link farm or redirection mechanism. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating the PDF is designed to host many links on disposable domains. While no scripts were explicitly extracted, the presence of external URIs and the overall structure point towards a phishing or malware distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://www.edutechusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/16135959e2c127---ruwamumodaxasopaxefidu.pdf In PDF document text
    • http://xinchenfast.com/upload/file/lizufadisimovekax.pdfIn PDF document text
    • http://hndgyl.com/v15/Upload/file/202199326149575.pdfIn PDF document text
    • http://richmore.kr/uploadfile/fckeditor/file/37896104214.pdfIn PDF document text
    • http://www.chubsorn.com/file/files/xufodilosorowuveletij.pdfIn PDF document text
    • http://hlqh.net/userfiles/file/20210902170446_973451337.pdfIn PDF document text
    • http://phuocthuan.vn/images/pic/file/13582521274.pdfIn PDF document text
    • http://devitohomesorlando.com/userfiles/files/diwuzujalofof.pdfIn PDF document text
    • http://yummyschool.com/_UploadFile/Images/file/jagijimaniwirefaziwodefu.pdfIn PDF document text
    • https://tradegateindia.com/userfiles/file/ziwixuxevemizolasaguf.pdfIn PDF document text
    • http://apartmany.cucoriedka.sk/data/files/mabamugevasu.pdfIn PDF document text
    • http://fsnmmaterials.com/UPFILE/userfiles/files/40100753477.pdfIn PDF document text
    • http://taiwanquinoafamily.com/shopadmin/upload/files/33437388420.pdfIn PDF document text
    • https://bczenekar.hu/files/file/gadamatasagawaberesama.pdfIn PDF document text
    • https://semut73.com/contents/files/90757197156.pdfIn PDF document text
    • https://a1-recruitment.fr/v2011/Files/fck_upload/file/60069795117.pdfIn PDF document text
    • https://patriciogaete.com/upload/file/71264406758.pdfIn PDF document text
    • https://rux-thai.com/ckfinder/userfiles/files/56495995833.pdfIn PDF document text
    • https://maintogelonline2.bet/contents/files/sipesakaru.pdfIn PDF document text
    • https://panoramabyty.cz/content/lebita.pdfIn PDF document text
    • https://tpk-m.ru/files/file/ninosawenubinafajata.pdfIn PDF document text
    • http://capriololaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/vadavipajubobupixo.pdfIn PDF document text
    • http://billsky.ee/files/file/88662808772.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/S30rS-6n6vg/uplcv?utm_term=run+app+in+emulator+android+studioPDF 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_off0000de82.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE82 17388 bytes
SHA-256: 5c72db946c95da8d5fabe77c990b8e482a8096f7a43c35d6657b3071932ec7c4
font_01_sfnt_off00010c11.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C11 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012428.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12428 10700 bytes
SHA-256: 1bbfcc78b955948c00c11706dd7a20bacaef688a302bba79b97d0de2c971a6f6