Malicious PDF — malware analysis report

Static analysis result for SHA-256 a523261da23f8ad2…

MALICIOUS

PDF

61.7 KB Created: 2021-06-17 22:17:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 4d30ee29833550997854fbb4ad05ba94 SHA-1: a73e59876a516736ff26594228d6fc4d7cd6cc77 SHA-256: a523261da23f8ad27530445df0be4fc273629a9a1fb712fa68f0aed14c83a92d
156 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Multiple heuristics identified it as a link farm pointing to compromised or disposable hosting, suggesting it's used to redirect users to malicious sites. The embedded URLs and the PDF structure itself are indicative of a phishing or malware distribution lure, likely delivered as a spearphishing attachment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9779

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
  • PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser failed: PDFSyntaxError. Static heuristics still ran and any of their findings above are valid; only the differential cross-check signal is missing.
  • 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://adlinefor.com/home/webagen/public_html/korn/data/file/zusupoziximileda.pdf
    • https://bataretak.com/img/files/file/jisoku.pdf
    • http://akbmodel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607e09766785b---xasokesigubimuvosagibipug.pdf
    • https://playgametoday.ru/wp-content/plugins/super-forms/uploads/php/files/961bc260256ae08e066cb4695be3fef8/rufovunikewakibumosarub.pdf
    • https://sellerflows.com/wp-content/plugins/super-forms/uploads/php/files/1f99af8ada6bd87031223d5f9e4c5dab/vosiwupukojokaduga.pdf
    • https://beribuket.ru/wp-content/plugins/super-forms/uploads/php/files/a4bd99c662db4fca0e13d6dd6af0d436/43458576831.pdf
    • http://tz5168.com/uploadfile/image/2021/05/16/file/20210516_172306_102.pdf
    • https://www.sblending.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1608176a68fba1---10988267760.pdf
    • https://israelonthehouse.com/wp-content/plugins/formcraft/file-upload/server/content/files/160af6d76aabe7---goweluxa.pdf
    • http://tomaszskiba.com/userfiles/file/50134018369.pdf
    • https://study-go.info/wp-content/plugins/super-forms/uploads/php/files/bd20fb05449c7dc9a3bf95754dbbc444/41585796556.pdf
    • https://discoverapartmentsforrent.com/wp-content/plugins/super-forms/uploads/php/files/2d55b73e125139b665c6aca0a64fc817/xajaxikogizakonepol.pdf
    • https://telewebmarketing.com/FCKeditor/file/xuwabomoberojiwivuruju.pdf
    • http://altinay-law.com/images/file/jaxajebasonekuguzuviraduz.pdf
    • https://www.davidcosz.de/wp-content/plugins/super-forms/uploads/php/files/od2oinarpcvm05kh1hs6pcq3l1/30813241509.pdf
    • http://aarogyamedico.com/userfiles/file/kugawawutoxopiba.pdf
    • http://ztkammer.at/uploads/file/414328891.pdf
    • http://tavernadelsnoguers.com/wp-content/plugins/super-forms/uploads/php/files/86da987f83661a683d552bdf1c08e947/sofisilosoxosikigaf.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://feedproxy.google.com/~r/skout/mBVl/~3/S30rS-6n6vg/uplcv?utm_term=if+syntax+in+c
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c17d.bin
c358d849403cb242bcebbe2543d4e2cb0a26231bd643cea457be51d73fdcf677		 pdf-font-stream PDF embedded font (sfnt) at offset 0xC17D 4856 bytes
font_01_sfnt_off0000d227.bin
2b4a9c1445ea51f9eb671425851b33fdf9fdc6342125fb3eb661172caf1d8854		 pdf-font-stream PDF embedded font (sfnt) at offset 0xD227 10480 bytes

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