Malicious PDF — malware analysis report

Static analysis result for SHA-256 a105c81dd6cdacf2…

MALICIOUS

PDF

103.3 KB Created: 2021-07-15 23:05:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: b3343df9f952280865a0b3f8d69ad87c SHA-1: 90fa3461d012ca7dbd9a19c0399370c9971701de SHA-256: a105c81dd6cdacf25a9d503d93a34b3a2bbbdf09ad4144882ea24cbc0673bb85
156 Risk Score

Malware Insights

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

The PDF contains numerous links pointing to compromised WordPress sites, identified by heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM'. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The document body is unreadable, but the link farm structure is a common tactic for spreading malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9926

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://www.sir.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16070fd38d8907---62874560611.pdf
    • https://www.acptechnologies.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b7adac9581---gigewubaroparoge.pdf
    • https://www.lumisolar.pe/wp-content/plugins/formcraft/file-upload/server/content/files/1608ab9d803f2f---sekulazok.pdf
    • http://cuanhuadanang.vn/uploads/image/files/jisow.pdf
    • https://nolimitscenter.be/peausitive/images/FCKeditor/file/4046482710.pdf
    • http://visualpaint.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608637adea2f2---wofenafasepug.pdf
    • http://uyaviation.com/wp-content/plugins/formcraft/file-upload/server/content/files/16096d41523952---kapefune.pdf
    • https://athensviptour.com/wp-content/plugins/super-forms/uploads/php/files/47c932d9937b8eefdab5c2db5009ac89/50455630256.pdf
    • https://thehamptonsbloomington.com/wp-content/plugins/formcraft/file-upload/server/content/files/16091482844e5c---jumegaxijajuwezuwiruli.pdf
    • http://jyotiacademicpress.org/uploads/file/kowapenonab.pdf
    • https://baatco.com/ckfinder/userfiles/files/mupusuriwelerolaxeninubaz.pdf
    • http://www.opencalgary.org/wp-content/plugins/formcraft/file-upload/server/content/files/160c669519fe81---43680211920.pdf
    • https://vmkstroi.ru/wp-content/plugins/super-forms/uploads/php/files/d75fc0c97ce73ca802d1c73de2dbb06c/mazufarijage.pdf
    • http://www.herbertvanderbrugghen.nl/draft/7915699278.pdf
    • http://cayxaotamphan.net/userfiles/image/file/23674706205.pdf
    • http://swaving-stalinrichting.nl/ckfinder/userfiles/files/96133373319.pdf
    • https://dacinsara.ro/fckfiles/file/lefovu.pdf
    • http://daiichilogistics.com/uploads/news_file/wemokalobivibixevufusa.pdf
    • http://brighterhealthcare.co.uk/wp-content/plugins/super-forms/uploads/php/files/c1ssjj03gipmssclqtuh63n4dp/vagaxuzopolazif.pdf
    • https://hyosungulf.com/uploads/file/zimufamuxavemipiw.pdf
    • http://accessprecision.com/userfiles/file/janezupanitafisoku.pdf
    • https://www.drmarlenebothma.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160df19b44909f---99788291338.pdf
    • http://bazatalty.pl/wp-content/plugins/super-forms/uploads/php/files/415569fc155a3f95abf547fe544a84e6/lasunozadirimugutufisolu.pdf
    • https://law.com.sg/wp-content/plugins/super-forms/uploads/php/files/21862c79513ffb05f8a84e1ae67c0a2a/59019154827.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/DOqCt-cVA4I/uplcv?utm_term=universal+coupling+assembly+drawing+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_off00013195.bin
b3edc68e9b9503ac51c12db6c40a8fc4a424d34bd4a22c3d4ed01c0231f611ad
pdf-font-stream PDF embedded font (sfnt) at offset 0x13195 16956 bytes
font_01_sfnt_off00015d71.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x15D71 16792 bytes
font_02_sfnt_off00017588.bin
6eab9b097d6abd116eb0a19a23cd67ec10dc8741ed0cb834d261b428eb92fe56
pdf-font-stream PDF embedded font (sfnt) at offset 0x17588 11380 bytes