Malicious PDF — malware analysis report

Static analysis result for SHA-256 a1d31530afbc266b…

MALICIOUS

PDF

69.3 KB Created: 2021-09-26 12:29:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 83e6052376adbdaea492244baebb2f78 SHA-1: f20bb748108e1c4a856b0f64f6e9c070581472e2 SHA-256: a1d31530afbc266bf717a53fa545999189b1117876175fd716846907e3145b4c
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The sample is identified as malicious by ML classifiers and ClamAV, indicating a phishing or trojan threat. Heuristics reveal it functions as a link farm, directing users to compromised WordPress uploads and disposable hosting sites, likely to facilitate credential harvesting or malware delivery. The presence of numerous external URIs and the PDF_SEO_DISPOSABLE_LINK_FARM heuristic strongly support this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9916

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://irlanc.ru/uplcv?utm_term=icloud+emails+on+android PDF link annotation
    • http://pokwuttibut.com/file_media/file_image/file/70777074148.pdfIn PDF document text
    • http://www.kindytennis.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614faeb33dec3---32034410590.pdfIn PDF document text
    • http://csc0898.com/userfiles/file/20210902182258_4clawd.pdfIn PDF document text
    • https://horgaszvelem.elelmiszer-hazhozszallitas.hu/ckfinder/userfiles/files/4247325190.pdfIn PDF document text
    • http://artpolinakuzina.ru/pict/file/zufew.pdfIn PDF document text
    • http://francescofesta.it/userfiles/files/7772293645.pdfIn PDF document text
    • https://www.saenger-ohg.de/wp-content/plugins/formcraft/file-upload/server/content/files/16141e5a426d82---dutuvuv.pdfIn PDF document text
    • https://andhimazhai.com/images/files/77731724013.pdfIn PDF document text
    • http://nnk.gr/wp-content/plugins/formcraft/file-upload/server/content/files/16145b95f8db35---80069177722.pdfIn PDF document text
    • http://highlevel.pl/userfiles/file/xibezerosonivigapi.pdfIn PDF document text
    • http://guojingmall.com/userfiles/file///74143837776.pdfIn PDF document text
    • https://jdbailbonds.com/wp-content/plugins/super-forms/uploads/php/files/6bf4499aec3121327c795a9910fccd9a/44929228542.pdfIn PDF document text
    • https://evocative.ru/wp-content/plugins/formcraft/file-upload/server/content/files/161341b6bb66cd---xesamexefubalu.pdfIn PDF document text
    • http://cokhitienvuong.com/uploads/files/12399436220.pdfIn PDF document text
    • http://pngroup.pl/ckfinder/userfiles/files/reginegadipenugizegora.pdfIn PDF document text
    • https://cncostruzioni.com/userfiles/file/10023731919.pdfIn PDF document text
    • http://noithatmyhome.com/img/files/88132968931.pdfIn PDF document text
    • http://theemasternetworker.com/ckfinder/userfiles/files/jixesadiniliriju.pdfIn PDF document text
    • http://sapaelitehotel.com/webroot/img/files/wikiwepof.pdfIn PDF document text
    • http://szcftz.com/upload/vovalakefodumotupasuse.pdfIn PDF document text
    • http://bilmatbasim.com/userfiles/file/libinagoxesuditi.pdfIn PDF document text
    • https://svarovanijelinek.cz/ckfinder/userfiles/files/piselalijubamudazosaf.pdfIn PDF document text
    • https://wickedcheesy.com/images/file/vereduxafelebakojex.pdfIn 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_off0000b2aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB2AA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cabc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCABC 17332 bytes
SHA-256: 5f8de041f728847beaf53df74712e1dd9cc7328f98cbecbf74285f82aa717264
font_02_sfnt_off0000f6ce.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6CE 10484 bytes
SHA-256: 1ed2fafeae52b3492d21b9d6183e3a9b7f24ddb99ca61a1f84e6c656fb12d7fe