Malicious PDF — malware analysis report

Static analysis result for SHA-256 a39a8844021d4d2a…

MALICIOUS

PDF

89.8 KB Created: 2021-09-16 00:51:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 7c8d3efd5e857d3b92f70c5757fd769a SHA-1: e3a7edb632194d5fcd9281983a440017f78bf64c SHA-256: a39a8844021d4d2a6788f9cc9de119bbdb48f03a661bdcba8b8677ed2856432d
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external URIs and is flagged as a link farm on disposable hosting, suggesting it's used to redirect users to potentially harmful sites. The presence of embedded URLs and the PDF structure point towards a phishing or malware distribution scheme, likely initiated via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9913

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://philabc.ru/uplcv?utm_term=como+crear+un+tema+para+android PDF link annotation
    • http://emachn.com/data/attachment/file/lorulafevojakem.pdfIn PDF document text
    • https://tl-systems.hu/files/files/86981629087.pdfIn PDF document text
    • http://osmed.cz/app/webroot/files/files/39690019520.pdfIn PDF document text
    • http://heimundsicherheit.de/userfiles/file/11670088334.pdfIn PDF document text
    • https://alatheir.com/atheirwsfiles/file/94528659227.pdfIn PDF document text
    • http://wefocusdesign.com/upload/files/narewuj.pdfIn PDF document text
    • http://le-nora.com/userfiles/file/90037381173.pdfIn PDF document text
    • http://www.marsagri.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613aae88e6703---2626940575.pdfIn PDF document text
    • http://batistar.fr/userfiles/file/27214836855.pdfIn PDF document text
    • https://www.meditech.cz/ckfinder/userfiles/files/zusaxurolakobudafefa.pdfIn PDF document text
    • https://weldingportal.it/userfiles/file/dilapoputi.pdfIn PDF document text
    • http://paddockj.com/user_data/editor/ckfinder/core/connector/php/upload/files/84456752840.pdfIn PDF document text
    • https://sealskinz.ru/files/file/fubagivuwebewatetizukeses.pdfIn PDF document text
    • https://supermagnum-bg.com/ckfinder/userfiles/files/80084092855.pdfIn PDF document text
    • https://uclerbaklava.com/resources/file/ratanode.pdfIn PDF document text
    • https://bodzlomu.com/userfiles/file/19969311690.pdfIn PDF document text
    • http://webinaris.training/ckfinder/userfiles/publics/files/goxaku.pdfIn PDF document text
    • http://zzfcw.com/file/fkimg/file/9467931059.pdfIn PDF document text
    • http://banlinhkienlaptop.com/userfiles/file/nudovisimuwamojowagiba.pdfIn PDF document text
    • http://rothemtour.com/FileData/ckfinder/files/20210908_016BDEA936BA52A8.pdfIn PDF document text
    • https://transport-vehicules.fr/userfiles/file/23440788365.pdfIn PDF document text
    • http://52fotki.ru/ckfinder/userfiles/files/pubemijasepekokolobuza.pdfIn PDF document text
    • http://leeharringtonhomes.com/userfiles/file/pasolinusi.pdfIn PDF document text
    • http://cancercareresearch.com/userfiles/file/filoxegewugegarunerevi.pdfIn PDF document text
    • https://ecableapp.com/FCKeditor/FCKimgUpload/file/bazej.pdfIn PDF document text
    • http://www.kreasoft.mx/wp-content/plugins/formcraft/file-upload/server/content/files/1613dc6c77c139---69398220051.pdfIn PDF document text
    • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f687.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF687 19100 bytes
SHA-256: 710a6ceb0996d2ec7d21af2ca435d78b8eec404d0829e11e8c0cfac64bbbf125
font_01_sfnt_off00012741.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12741 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013f58.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13F58 10592 bytes
SHA-256: 81cec9ffd6b4c759a08f5463d7c8d28d2a4468b6b8f6acce62c29e80a90466dc