Malicious PDF — malware analysis report

Static analysis result for SHA-256 99137db4557f63f1…

MALICIOUS

PDF

84.6 KB Created: 2021-06-25 23:07:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 3b0ee1671bf3dacd456782daabeb9c03 SHA-1: ae016d556f8e0fb3d8e07f1045243f6cc859e385 SHA-256: 99137db4557f63f104ae291c5573394dbfd391f53b026f916d08593c123461de
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous links, many pointing to compromised WordPress sites, suggesting a link farm designed to distribute malicious content or phish users. The ClamAV detection and ML classifier strongly indicate malicious intent. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but likely serving as a vessel for the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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 https://infrive.ru/uplcv?utm_term=history+of+art+and+architecture+pdf
    • https://allianceflooring.net/wp-content/plugins/super-forms/uploads/php/files/d1b3775c6574649a05d69066ddbac075/demam.pdf
    • http://redwoodpwr.com/wp-content/plugins/super-forms/uploads/php/files/p1uhqqpqqi5rekohtqqorhtjp3/vuweje.pdf
    • http://arlingtonhigh1961.com/clients/e/ef/ef36f0800c0a5d5a0b00d5ecc8c3c6da/File/tugofofopopojiguwudesi.pdf
    • https://kolbandibileklik.com/resimler/files/finifogi.pdf
    • https://keluargamimpi2.com/contents//files/25884153925.pdf
    • https://sgdivorcelawyers.com/wp-content/plugins/super-forms/uploads/php/files/4935e8c25c5442a46e992a2774f13686/lodematexejajemagunonebel.pdf
    • https://eandjfamilyhealthcenter.com/wp-content/plugins/super-forms/uploads/php/files/f523e483ef93949bffc11af4a4a78cfc/movezez.pdf
    • http://www.aluvascientific.com/UserFiles/file/digumopuzus.pdf
    • https://lightspec.ca/wp-content/plugins/super-forms/uploads/php/files/c67b813af4013cadaa73f5d3c1136a1d/sukofebutekiw.pdf
    • https://www.booster-p.com/wp-content/plugins/formcraft/file-upload/server/content/files/160871e3928262---74698432474.pdf
    • https://www.beadvised.co.uk/wp-content/plugins/super-forms/uploads/php/files/cb07cfb2d8f604140c0ddc80e144989d/titiwimajawafekexuzod.pdf
    • http://whs1963.com/clients/7/75/758a827d59fb1c2827eec60421ffdc22/File/1954676213.pdf
    • http://aliceinformaticasrl.com/user/pages/48403734655.pdf
    • http://www.climatisur.com/ckfinder/userfiles/files/71623821755.pdf
    • https://www.hungarianassociation.com/wp-content/plugins/formcraft/file-upload/server/content/files/16098b1a55bd98---bimofatediganugelevib.pdf
    • http://intergeored.com/upload/File/97625613468.pdf
    • https://primax.fr/wp-content/plugins/super-forms/uploads/php/files/kr8cvr58e45338cdnnnv2fid51/bafaxipazadedivoko.pdf
    • https://siyata.co.il/wp-content/plugins/formcraft/file-upload/server/content/files/160abfb0584c2a---pegoxunavutiluduletu.pdf
    • http://compie.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160b2541aabb57---xopilo.pdf
    • https://beaufortbond.com/wp-content/plugins/super-forms/uploads/php/files/eddce6db82aa4e506b1d1d27fed66b52/tesusavevorabalawefulukud.pdf
    • https://dovolena-jiznicechy.cz/uploads/74308110654.pdf
    • http://kanstm.com/ckupload/files/19098320230.pdf
    • https://advicezone.org.uk/wp-content/plugins/super-forms/uploads/php/files/apirbirp38ki4cv029rf5f7nqa/5523949699.pdf
    • http://middlegeorgiacoinclub.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609f1ca3b326f---15653133362.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e8b0.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xE8B0 16792 bytes
font_01_sfnt_off000100c7.bin
6b828097a0ef9f2912aed18b53d0e66ab5a99aef1cde38d243ddd9e5082602da
pdf-font-stream PDF embedded font (sfnt) at offset 0x100C7 10876 bytes
font_02_sfnt_off000119de.bin
7df2f51fa241b08d61ed7f03656e451b8cd3951cc3b30d9c15667176285edc7d
pdf-font-stream PDF embedded font (sfnt) at offset 0x119DE 16796 bytes