Malicious PDF — malware analysis report

Static analysis result for SHA-256 a31d8c4dc57ebf81…

MALICIOUS

PDF

100.7 KB Created: 2021-08-15 13:54:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-16
MD5: cb01102c3474cab625705870c3e1d976 SHA-1: 1de192f4358d06522d733d94f9cb06da585699e2 SHA-256: a31d8c4dc57ebf81300eae61f13339c0120afb297dee7e3eea42284ec77a95a2
156 Risk Score

Malware Insights

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

The file is identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. Heuristics reveal it functions as a link farm, pointing to numerous PDFs hosted on compromised WordPress sites. The presence of multiple external URIs and the structure suggest it's designed to lure users to malicious content, likely for phishing or further malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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://alvasari.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c980177934c---36223363884.pdf In PDF document text
    • https://ceilford.org/wp-content/plugins/super-forms/uploads/php/files/745c595e37772a44e06083e398fc78e8/82232181641.pdfIn PDF document text
    • http://remobudostol.pl/pliki/soneduz.pdfIn PDF document text
    • https://tavio.ru/files/file/filajapumupimupijubikigev.pdfIn PDF document text
    • http://cabini.it/userfiles/files/37443732033.pdfIn PDF document text
    • http://www.pointcookelectrician.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160c86480c3ecf---gazajurezisumudawuv.pdfIn PDF document text
    • http://www.neslihanonur.com/wp-content/plugins/super-forms/uploads/php/files/06b9de7877e33705567a631bc1acfdad/mezixijofosarajiku.pdfIn PDF document text
    • http://trenermichal.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160889baa7e2f4---70487341109.pdfIn PDF document text
    • http://closehorses.com/userfiles/file/gulavilokodep.pdfIn PDF document text
    • http://secureyun.cn/uploadfile/file///2021080322450367.pdfIn PDF document text
    • http://apsara.ru/userfiles/file/wowojesivozegadigevejusa.pdfIn PDF document text
    • https://cruiseship.cruises/wp-content/plugins/super-forms/uploads/php/files/t2koo7i8uciupm3nojtsm0pm23/vevasorebokabujuke.pdfIn PDF document text
    • https://lose-weight.tw/upload/files/33535593446.pdfIn PDF document text
    • http://www.recko.ru/ckfinder/userfiles/files/60396800648.pdfIn PDF document text
    • https://alfa-clining.ru/wp-content/plugins/super-forms/uploads/php/files/9f2352b897977c5eeedab4b7abda7a95/wisumanomerokenudibuxazor.pdfIn PDF document text
    • http://iwish-cosmetics.com/wp-content/plugins/formcraft/file-upload/server/content/files/160cbfdb2cd1db---47332455236.pdfIn PDF document text
    • http://ipjanah.ir/wp-content/plugins/super-forms/uploads/php/files/73p7dubtb3a8rb42pf333ssiu7/56278391841.pdfIn PDF document text
    • https://mattweidnerlaw.com/wp-content/plugins/formcraft/file-upload/server/content/files/1611822086a182---10660619536.pdfIn PDF document text
    • https://evboosters.com/wp-content/plugins/super-forms/uploads/php/files/3604bb67ee37737aa49acf180a4b064b/todin.pdfIn PDF document text
    • https://www.mclarenpress.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606d30319672e---45156684269.pdfIn PDF document text
    • http://stroynerud-sm.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160c5fde8015fc---39760921044.pdfIn PDF document text
    • http://www.gainerwindows.ca/wp-content/plugins/super-forms/uploads/php/files/hgh0armpgak2toksn858184uj4/bizupowog.pdfIn PDF document text
    • https://livingcircles.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160780cebe6e41---ruwirelasoda.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/zMnd8XtcwSM/uplcv?utm_term=ejercicios+de+simplificacion+de+fracciones+algebraicas+con+exponentesPDF 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

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00011d94.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11D94 11316 bytes
SHA-256: e7364c0576b469772dc8a4f1df8ca98097855796f18c9cd9c39dfa8bb8c9cfbd
font_01_sfnt_off000137b5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x137B5 20104 bytes
SHA-256: f66df90f65c4f9e22ad436d229d8ee51564cff7efd46e941629b14b70c13488a
font_02_sfnt_off00016b73.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16B73 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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