Malicious PDF — malware analysis report

Static analysis result for SHA-256 a73f540ea25e91f0…

MALICIOUS

PDF

82.2 KB Created: 2021-09-20 09:34:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 61387e4e14c72ff16af2295c408f03ff SHA-1: b6fc349f7353583087bb99ca3180a9289d18f862 SHA-256: a73f540ea25e91f0ec404020e95dbbf17fdd181baae3213cd224604e6183107b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is a PDF containing numerous links to external websites, many of which are hosted on compromised WordPress sites or disposable domains, indicating a link farm for phishing or malware distribution. The ML classifier and ClamAV detection strongly suggest malicious intent. Although no scripts were explicitly extracted, the PDF structure and embedded URLs are indicative of a phishing lure, likely delivered as a spearphishing attachment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://infrive.ru/uplcv?utm_term=avast+mobile+security+pro+free+download
    • http://shangrilayunnan.com/ckfinder/userfiles/files/22876896648.pdf
    • https://konyaalotaksi.com/userfiles/file/sifabaxulilul.pdf
    • http://salamatekhanevadeh.ir/ckeditor/files/files/rokesuvumilazu.pdf
    • http://flex-link.cn/uploadfiles/files/wuriberujofexumiruvusumu.pdf
    • http://www.truca-taoules.com/ckfinder/userfiles/files/pubijedovaj.pdf
    • http://mamnonsaokhue.vn/app/webroot/files/ckfinder/files/44093172795.pdf
    • http://csc-020.com/userfiles/file/20210919113039_dmzc1b.pdf
    • https://www.tamilsaga.com/ckfinder/userfiles/files/gidonumadod.pdf
    • http://hla.vn/upload/files/33505492235.pdf
    • https://callmarkinvestments.fortunekenya.com/callmark/files/8877105224.pdf
    • https://christianboudreau.com/wp-content/plugins/formcraft/file-upload/server/content/files/16143606d51718---ragatufuwafidefisizokaf.pdf
    • http://musikpark-live.de/userfiles/file/zoluwuxadine.pdf
    • http://www.iqubz.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613a1866715e8---givakusuzub.pdf
    • https://pierreseche.fr/userfiles/file/22323424833.pdf
    • https://totalyoumovement.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614060caa373e---vopifovulenoxanijivi.pdf
    • http://jungam21.com/upfiles/file/1630527517.pdf
    • https://takarasushimn.com/userfiles/files/lijore.pdf
    • http://wimborst-ceramics.nl/ckeditor/ckfinder/userfiles/files/89784690416.pdf
    • http://www.moyekolodin.com/files/dituzofufafukivukatikit.pdf
    • http://nepodoshlo.kz/ckfinder/userfiles/files/dorezobanipedogufinogavu.pdf
    • https://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/161441878b4de8---jorexewutebetizidirisik.pdf
    • https://skinrepublic.vn/webroot/img/files/44427911439.pdf
    • http://shiokuda1.com/contents/files/48058515358.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_off0000daba.bin
3a3fe9d69859c4a6ff340bd2207af5eb1fe6e238950da972cb56fe3f6fdc23b6
pdf-font-stream PDF embedded font (sfnt) at offset 0xDABA 17560 bytes
font_01_sfnt_off00010824.bin
a62a36f2724e1b6b354cd6bec68ca0e71587234ba8a5904c6701df4f873ba7c9
pdf-font-stream PDF embedded font (sfnt) at offset 0x10824 11268 bytes
font_02_sfnt_off0001227a.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1227A 16792 bytes