Malicious PDF — malware analysis report

Static analysis result for SHA-256 81d456c6e1ea8cff…

MALICIOUS

PDF

78.5 KB Created: 2021-09-24 17:47:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: f5a851a3a444ae793335829f7a8bcd1a SHA-1: f57195130338bb121912dff0007956ccafdf5c6f SHA-256: 81d456c6e1ea8cff365c4219984e75574699bf3f01fa4d590885fd619fa1d2c7
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ClamAV and an ML classifier, with heuristics indicating it functions as a link farm. Several URLs point to compromised CMS uploads or disposable hosting, suggesting an attempt to distribute malicious content or phish users. Although no scripts were explicitly extracted, the PDF structure and embedded URLs strongly suggest a phishing or malware distribution vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

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 http://agarimo.com/archivos/archivos/17149235250.pdf In PDF document text
    • http://goref.ru/files/file/vabutomilaboxonesi.pdfIn PDF document text
    • http://acudrved.com/ckfinder/userfiles/files/9608769117.pdfIn PDF document text
    • http://conservationenergy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614c99811d685---84739603437.pdfIn PDF document text
    • https://pui-vital.ro/msg_media/file/90202544928.pdfIn PDF document text
    • https://westcoastmovers.ca/wp-content/plugins/super-forms/uploads/php/files/airnkd9pmhnhnum23ulu1rggua/35690768608.pdfIn PDF document text
    • http://bookblog.kr/data/file/files/92954878387.pdfIn PDF document text
    • https://tannhatviet.vn/upload/files/41765578549.pdfIn PDF document text
    • https://himalayanwanderer.com/himalayan/userfiles/files/64049791405.pdfIn PDF document text
    • https://www.assofmt.org/ckfinder/userfiles/files/bemiforokemukore.pdfIn PDF document text
    • http://webbyshoe.com/fckeditor/userfiles/file/85940770559.pdfIn PDF document text
    • https://peisheng.org/uploads/ckfiles/files/613e2599e7a5a.pdfIn PDF document text
    • http://shtaket46.ru/page_edit/_samples/userfiles/files/fabiretagivus.pdfIn PDF document text
    • https://malimbe.africa/wp-content/plugins/super-forms/uploads/php/files/e0d995195df255697ea87a82e9b1484a/82853577094.pdfIn PDF document text
    • https://kiptep.ru/file/19344568490.pdfIn PDF document text
    • https://manorhair.com/uploads/files/202109230050459161.pdfIn PDF document text
    • http://thessalonikiflights.com/files/files/8739020277.pdfIn PDF document text
    • http://otworz-biuro-podrozy.pl/userfiles/file/91011677093.pdfIn PDF document text
    • http://diegogenna.it/userfiles/files/25104885027.pdfIn PDF document text
    • http://glassick.com/userfiles/file/97561694973.pdfIn PDF document text
    • https://vwb.mrv-educationservices.com/content_file/files/zemuposusijokugakolu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=presidentes+de+mexico+y+sus+aportaciones+mas+importantes+pdfPDF 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b104.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB104 11052 bytes
SHA-256: aefb41deafc46423e3162b6966ab52d12d08ae59e19e8095dd246aa03f19a921
font_01_sfnt_off0000cacd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCACD 17964 bytes
SHA-256: 436ae934703db13fa3a08ad83d54ea42f0fa30d179e10d820d9e4ec949bf27c1
font_02_sfnt_off0000e6de.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6DE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_03_sfnt_off0000fef0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFEF0 17620 bytes
SHA-256: 61fc6d33c24df1ab8409bb14186e0228ef1de7035f0e37fc17c537e8272b3abb