Malicious PDF — malware analysis report

Static analysis result for SHA-256 b431057758a9f8e7…

MALICIOUS

PDF

91.8 KB Created: 2021-10-05 03:09:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 3ddf81c99be74bcb254453b67fda9bd7 SHA-1: 6740d9797b506841440d158b1d578b3179edd4d2 SHA-256: b431057758a9f8e75c27bd9be043c2368937ec5b24f8d76490eedd1dec90fac2
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as a malicious PDF by ML classifiers and ClamAV, indicating it is likely a phishing or trojan delivery mechanism. The presence of numerous external URLs, many hosted on compromised WordPress sites or disposable domains, suggests a link farm designed to redirect users to malicious content. The 'SE_INVOICE_LURE' heuristic further supports the phishing pretext, aiming to trick users into clicking these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

Heuristics 7

  • 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.
  • Fake invoice / payment lure low SE_INVOICE_LURE
    Document contains invoice or payment language paired with an action verb — useful context when combined with link, macro, or attachment indicators
  • 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=please+can+you+confirm+receipt+of+this+email PDF link annotation
    • http://skyrybupaslaugos.lt/uploads/files/91141764034.pdfIn PDF document text
    • http://inlikeflintlogistics.com/wp-content/plugins/formcraft/file-upload/server/content/files/1615269d277d3e---vevoferuvata.pdfIn PDF document text
    • http://ricarda-allegra.de/userfiles/file/49950062918.pdfIn PDF document text
    • https://www.khaosanpools.org/ckfinder/userfiles/files/5096317764.pdfIn PDF document text
    • https://www.teppiche-waschen-hamburg.de/wp-content/plugins/formcraft/file-upload/server/content/files/1615445f4d53b7---duliwilopidurutok.pdfIn PDF document text
    • http://yokosohk.com/files/fckfiles/file/53412347288.pdfIn PDF document text
    • http://maschimaurizio.it/userfiles/files/56615747394.pdfIn PDF document text
    • http://www.urbanwaterways.info/files/kamitufuremikupozi.pdfIn PDF document text
    • http://igs.compcierge-asia.com/ckfinder/userfiles/files/1418072624.pdfIn PDF document text
    • http://www.espaciocultivarte.com/ckfinder/userfiles/files/33805831470.pdfIn PDF document text
    • http://cuanhuaabshanquoc.vn/files/babamilepatinulabonot.pdfIn PDF document text
    • https://xn----8sbaavnccwq4am.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/5c07bb134f345940e930894003ee9bbd/logawuwitopina.pdfIn PDF document text
    • http://canoto.us/Images_upload/files/dazosidosevuranuvulaz.pdfIn PDF document text
    • https://studiecarriere.it/uploads/file/91100199250.pdfIn PDF document text
    • https://totounited.com/contents/files/titazudusej.pdfIn PDF document text
    • http://veterina-naslunci.cz/userfiles/file/6895863867.pdfIn PDF document text
    • https://gulf-rope.com/images/bulk_images/files/dadisume.pdfIn PDF document text
    • https://sasalidayanisma.org/uploads/file/63421739328.pdfIn PDF document text
    • https://www.q-jin.ne.jp/ckfinder/userfiles/files/43959264184.pdfIn PDF document text
    • http://dragonspond.com/uploads/files/79599408600.pdfIn PDF document text
    • http://sva-jeanroze.com/xmedia/file/48459623737.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_off0000f5e3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5E3 10960 bytes
SHA-256: 241f9a2640990b38ec94ca9fa1eee92806c3706c48f00d88339a3c7c16c0bf5d
font_01_sfnt_off00010f2f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F2F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012741.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12741 22412 bytes
SHA-256: 7ac1d18e0e9a651cccf92e98a42b523d1fce9559937fce019aba75768f5338b6