Malicious PDF — malware analysis report

Static analysis result for SHA-256 decb2091f5d7e4f4…

MALICIOUS

PDF

68.2 KB Created: 2021-05-07 17:09:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 4a3f6baf8b47683bf15d8d2b551f2598 SHA-1: 15356ae7012f8e77c1c94a1313f69eed1a4700c4 SHA-256: decb2091f5d7e4f4b2fe973a9ccedcb8db5ffde4d7f94c9a18c93c3abed4963a
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous links to external websites, many hosted on compromised CMS uploads, suggesting it functions as a link farm to distribute malicious content or phish users. The presence of embedded URLs and the nature of the heuristics point towards a phishing or malware distribution campaign, likely initiated via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9995

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://southernlightingsource.com/wp-content/plugins/super-forms/uploads/php/files/6c94c220da9d1164ebae9fd17a0d03b4/86793795821.pdf
    • https://www.sgestrecho.es/wp-content/plugins/formcraft/file-upload/server/content/files/16073998aa1126---46592372336.pdf
    • https://wilsonbarrera.com/inicio/wp-content/plugins/formcraft/file-upload/server/content/files/1607dd4127ec95---xusefalipusod.pdf
    • http://almar-bus.pl/userfiles/file/negusekifirijusavad.pdf
    • https://gdr.co.il/wp-content/plugins/super-forms/uploads/php/files/2f51ae918b3275feeb55e9816a7e79d7/33199023703.pdf
    • http://aite-materials.com/upfiles/file/guvivu.pdf
    • http://julieesteban.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607bb41e7a99f---bideputemegefenebi.pdf
    • https://www.projectorrentals.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608b0d535eee7---20510416097.pdf
    • http://avtoarka.ru/wp-content/plugins/super-forms/uploads/php/files/17d4c3f3559fd04c8a6c24b66a3fd5e1/ralufidaluxa.pdf
    • http://english-island.pl/wp-content/plugins/super-forms/uploads/php/files/51m0eln7turctc6as6ojc88f53/sawaketaxa.pdf
    • http://www.tif.cn/wp-content/plugins/super-forms/uploads/php/files/5ka43ebpckor1rc423l997idsp/49614031277.pdf
    • http://www.adanakursmerkezi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609444e11d8b3---xowadujidafibut.pdf
    • https://brunoamaranti.it/wp-content/plugins/super-forms/uploads/php/files/p148mhrk0mdno54of1fna5jil6/93590069836.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=spanish+to+english+pocket+dictionary+pdf
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d4dc.bin
41363f32956496a229ec3b8033f31f137c33ee6477bf734d867bff59d4d97003		 pdf-font-stream PDF embedded font (sfnt) at offset 0xD4DC 5688 bytes
font_01_sfnt_off0000e840.bin
b1f9a5f441304f44d5f4cd2c082eec62d4e9090ebf3ea254b0840a483813bdc8		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE840 10288 bytes

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