Malicious PDF — malware analysis report

Static analysis result for SHA-256 a537e9bd516ce043…

MALICIOUS

PDF

70.1 KB Created: 2021-10-04 02:34:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 79f1914e597e62dd3761bddd4159ac44 SHA-1: 0983dae7dc76dc764f9e601358172fbee3ca2f76 SHA-256: a537e9bd516ce043d99f42e5a47c82b7103cb330c35bcd3d6292f4810616366c
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was identified as malicious by ML classifiers and ClamAV, specifically flagged as Pdf.Phishing.Trojan. It contains a large number of external URLs, many of which point to compromised CMS upload directories or are hosted on disposable domains, indicating a phishing or scam attempt. The PDF structure itself is a link farm designed to redirect users to these malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9986

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://krisoc.ru/uplcv?utm_term=how+dividend+investing+works PDF link annotation
    • https://bbpartner.cz/userfiles/file/94109284687.pdfIn PDF document text
    • http://accapierre.it/userfiles/files/87587061912.pdfIn PDF document text
    • https://mami-m.com/Uploads/userfiles/files/fapun.pdfIn PDF document text
    • http://hotelrealerimini.it/userfiles/files/63780519758.pdfIn PDF document text
    • http://peoplefineart.com/assets/202109/files/20210903093052446997.pdfIn PDF document text
    • https://jf-orvalho.pt/userfiles/file/xibufazuteg.pdfIn PDF document text
    • https://www.zaantraining.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613d2948b5d53---1372834576.pdfIn PDF document text
    • http://oldstat.ww.tj/img/file/tibejinosuvazibogugamiz.pdfIn PDF document text
    • https://sandalyecenneti.com/wp-content/plugins/super-forms/uploads/php/files/jukcn09aklfb3ani6phcneuhkb/lixexatimidukizi.pdfIn PDF document text
    • http://www.gieskestukadoors.nl/ckfinder/files/files/gibijoxupawufitelolojom.pdfIn PDF document text
    • http://investinwielkopolska.pl/application/lib/ckfinder/userfiles/files/vebuzanobosuvorenuxibi.pdfIn PDF document text
    • https://oneremote.ru/wp-content/plugins/super-forms/uploads/php/files/a0804dc6b791f5002146dacb51131976/72096771529.pdfIn PDF document text
    • http://rgn2u.com/userfiles/files/voboxevaxoganixera.pdfIn PDF document text
    • http://skybuildinfraprojects.com/uploads/lowonemorigoxo.pdfIn PDF document text
    • http://corporatiegids.nl/uploads/files/kabaxalebav.pdfIn PDF document text
    • http://ptsound.com/plugins/ckfinder/userfiles/files/newag.pdfIn PDF document text
    • http://mg001.cn/upload_fck/file/2021-9-28/20210928113818268418.pdfIn PDF document text
    • http://richardchong.com/userfiles/files/xobamutilolafatida.pdfIn PDF document text
    • https://bustotoronto.com/userfiles/file/92267747185.pdfIn PDF document text
    • https://dhrc.in/userfiles/file/sepuzivunobizidotuv.pdfIn PDF document text
    • http://maristaslardero.es/userfiles/file/xemovafoji.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_off0000b030.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB030 16708 bytes
SHA-256: d9262ed308601278a67320de1ed846b26a9cbe3829ae4ee25acc8a153ac9a08d
font_01_sfnt_off0000dadc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDADC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f2f3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2F3 10448 bytes
SHA-256: 28d7f083fca8a40dfad9a3718d175f1b0233b7aa204d818193c6b5f688e4ee88