Malicious PDF — malware analysis report

Static analysis result for SHA-256 4d55758bb65cd1f4…

MALICIOUS

PDF

89.8 KB Created: 2021-09-22 13:50:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: da707609cbce7939bf5975d7f7437c00 SHA-1: 57573b88c875a71ad4740030b60959613050c737 SHA-256: 4d55758bb65cd1f4ffde8970c3587b9a1a033b15f4ee396a8f195849de6dd54a
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF was flagged by multiple heuristics as malicious, including ML classification and ClamAV detection, indicating a high likelihood of malicious intent. The presence of numerous external links, many pointing to compromised or disposable hosting, suggests a link farm designed to redirect users to malicious content. While no scripts were explicitly extracted, the PDF structure and link farm behavior are indicative of a phishing or malware distribution attempt, likely initiated via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

Heuristics 7

  • 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.
  • Urgency / deadline lure low SE_URGENCY_LURE
    Document contains urgency or deadline language ('account will be terminated', 'action required within 24 hours', etc.) — useful context, but low-signal without other findings
  • 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://jck.ro/userfiles/file/tajusomaviwomorokimulag.pdf In PDF document text
    • http://www.fullmooneye.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613056daed6c9---likolibijariru.pdfIn PDF document text
    • https://mudateconmigo.cl/wp-content/plugins/super-forms/uploads/php/files/6130a9d641efaba0386149f0d8daf029/kewaki.pdfIn PDF document text
    • http://www.village-gaulois.org/gestion/ckfinder/userfiles/files/tupaxitevuvipikun.pdfIn PDF document text
    • http://morethancars.nl/uploads/edytor/file/zozenogore.pdfIn PDF document text
    • http://phannhan.vn/files/usersfiles/files/fofatutulebelogukigakusir.pdfIn PDF document text
    • https://www.olympusnorge.no/wp-content/plugins/super-forms/uploads/php/files/n443vttvv3hjgaqu39ch6uq431/zoposanazekedopaketexune.pdfIn PDF document text
    • http://hyunsin.net/userfiles/file/susepidetilin.pdfIn PDF document text
    • https://beautydent.hu/editor_up/8182395522.pdfIn PDF document text
    • https://yarsan.ru/wp-content/plugins/super-forms/uploads/php/files/c0f4425fbbc2aefa9d43f57b03e487f6/10815919168.pdfIn PDF document text
    • https://perkunasstudio.com/uploads/files/202109051551222019.pdfIn PDF document text
    • http://studiovalecchi.it/userfiles/files/76307591734.pdfIn PDF document text
    • http://we-women.de/default/files/uploads/file/futepewakelofepax.pdfIn PDF document text
    • http://ilyxrace.com/userfiles/files/17329496408.pdfIn PDF document text
    • http://yaqeen-eg.com/userfiles/file/janomazipo.pdfIn PDF document text
    • http://spreewaldatelier.de/img/editor/file/segexigemizuxibipatalar.pdfIn PDF document text
    • https://pyccenter.com/images/Upload/file/2462029234.pdfIn PDF document text
    • https://zegaoyun.com/calisma2/files/uploads/kifeminipirefo.pdfIn PDF document text
    • http://augustaelectricalwork.com/editorData/file/5786314729.pdfIn PDF document text
    • http://antansconstructions.com/ckfinder/userfiles/files/topeziwovavopulosoxol.pdfIn PDF document text
    • http://www.xpresswedding.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e622296286---xamoridewajogatavasixune.pdfIn PDF document text
    • http://hmed.vn/upload/files/57475981955.pdfIn PDF document text
    • http://markasib.ru/ckfinder/userfiles/files/34510908921.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/6naE_Nh8_CY/uplcv?utm_term=brief+answers+to+the+big+questions+the+final+book+from+stephen+hawking+pdf+downloadPDF 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_off0000f032.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF032 20312 bytes
SHA-256: b728635d84147c06fd2c645bfee1e55c7b44b98ced6790e102c071403202557e
font_01_sfnt_off0001261e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1261E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013e35.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13E35 11560 bytes
SHA-256: 8cd02c4ee72302ea56501eb5c356a04dc1489ae0ed6e9f980d3e0b90d0318439

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