Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8863f84bd7f918a…

MALICIOUS

PDF

84.6 KB Created: 2021-09-13 18:06:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: f9df50f6b6f7f9a7e970e945af4982ef SHA-1: 4bd12a2dccf92432ef12ba4e949c1f0a175263e8 SHA-256: a8863f84bd7f918a7fc58b169f7d9ffc10a9e985e78fbc9daebdebf6ef4f9958
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous URLs pointing to various domains, some of which are associated with compromised CMS uploads or disposable hosting. The document body is unreadable binary data, suggesting it's not intended for direct user interaction but rather to host these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://pmfegypt.com/userfiles/files/vajodufedelinewagitudugi.pdf In PDF document text
    • http://dobrejaja.com/Upload/file/vuvobote.pdfIn PDF document text
    • https://asken.as/bilder/file/63510379945.pdfIn PDF document text
    • http://hurtglass.pl/upload/file/9268575169.pdfIn PDF document text
    • https://realxenon.ru/uploads/files/diwipob.pdfIn PDF document text
    • http://air-con.ru/upload/files/zedefenoka.pdfIn PDF document text
    • http://wernitznigg.at/files/nodesi.pdfIn PDF document text
    • http://dachastyle.com/userfiles/file/67066288386.pdfIn PDF document text
    • http://barrarioservicos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161351fcd0c10a---62043315570.pdfIn PDF document text
    • https://doanhnghiepvietnam.org/img_duhoc/files/rikexovikotixabapemud.pdfIn PDF document text
    • https://gastriklandsbf.se/UserFiles/files/22421127869.pdfIn PDF document text
    • https://alcc.vn/wp-content/plugins/super-forms/uploads/php/files/ciugad6td4uu76ks0j7ak9vh66/4049720646.pdfIn PDF document text
    • http://splhardware.com/UploadFile/file/2021091320121273499.pdfIn PDF document text
    • https://amgaa.org/temp/files/22444606874.pdfIn PDF document text
    • https://nguyenvanhuongloc.vn/app/webroot/files/images/pages/files/82555782864.pdfIn PDF document text
    • https://equinox-e.com/upload/UserFiles/file/15997216278.pdfIn PDF document text
    • http://ventima.ru/userfiles/file/gudomemig.pdfIn PDF document text
    • http://phannhan.vn/files/usersfiles/files/vosazuradebefitag.pdfIn PDF document text
    • http://xn--oy2b19v1mb1yi.com/userfiles/file/lenekokof.pdfIn PDF document text
    • http://veoguidecostarica.com/ci/userfiles/files/44631701749.pdfIn PDF document text
    • https://evocative.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1613ec9ad2476b---65815363016.pdfIn PDF document text
    • https://messianic.live/wp-content/plugins/super-forms/uploads/php/files/bda95be0638ca930218b31cfd93c5632/nepufidusuvezexizobot.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/A3Ryygt5BCM/uplcv?utm_term=600+degrees+in+radiansPDF 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_off0000ea23.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA23 16768 bytes
SHA-256: da6153657e7247d3273e2fb2b1c10f5812b5dd46e5e9b0483f282d2359a7c09a
font_01_sfnt_off0001159e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1159E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012db5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12DB5 10352 bytes
SHA-256: 168dedd23e0f6a23d0b554c20713aa341884c95d6f830491955539277617b427