Malicious PDF — malware analysis report

Static analysis result for SHA-256 41f91443ec32ea6f…

MALICIOUS

PDF

80.3 KB Created: 2021-09-14 08:34:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 8fa27d9550981e2d51a28d7586e18159 SHA-1: d28d395bf81cce53268bd3f9d46cc304e0ba4a65 SHA-256: 41f91443ec32ea6fc3f246ed35da07fef21182ae6015c43f2ddd6037e7d75c08
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external links, including one pointing to a compromised WordPress upload, and is described as a link farm on disposable hosting. The presence of these links suggests the PDF is used to redirect users to potentially malicious websites, likely for phishing or to download further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

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://cructi.ru/uplcv?utm_term=among+us+game+unblocked PDF link annotation
    • https://bimstudioinc.com/media/files/jawojeserujabiwobemu.pdfIn PDF document text
    • http://exim5.hu/_user/file/30815773799.pdfIn PDF document text
    • http://raegcafe.com/uploads/files/fokemuragusoromodonu.pdfIn PDF document text
    • http://marathon-gexin.com/Uploadfiles/files/82452788443.pdfIn PDF document text
    • http://dblbtech.com/userfiles/file/vafamorilawimitawa.pdfIn PDF document text
    • https://stpatswatertown.org/ckfinder/userfiles/files/bobisitomofute.pdfIn PDF document text
    • http://chicagohalo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612eecb4b1812---39714041285.pdfIn PDF document text
    • https://asiatravel.kg/wp-content/plugins/super-forms/uploads/php/files/53a31301b6791ab4ef452859120aefd1/5949724094.pdfIn PDF document text
    • https://rezilta.com/psum/admin/userfiles/file/4387791099.pdfIn PDF document text
    • https://dakhoathienhoa.net/images/files/wewimago.pdfIn PDF document text
    • http://innova-perila.ru/upload/files/69384472347.pdfIn PDF document text
    • http://nakajima-ya.com/upload/save_image/files/32232299616.pdfIn PDF document text
    • http://sportservistocik.cz/UserFiles/File/79164678803.pdfIn PDF document text
    • https://et-auditing.com/userfiles/files/70815345546.pdfIn PDF document text
    • http://netflor.pl/upload/File/tejoja.pdfIn PDF document text
    • http://architettosbaffo.com/userfiles/files/47736476632.pdfIn PDF document text
    • https://lingchuanfloor.com/app/webroot/userfiles/files/senibipaniki.pdfIn PDF document text
    • http://ks4073.com/file_media/file_image/file/guderirejoputitilatigegan.pdfIn PDF document text
    • https://callhfelectric.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138ef2e30115---22045906109.pdfIn PDF document text
    • https://textmakareknutsson.se/upload/image/69122062365.pdfIn PDF document text
    • http://zeshengtecphar.com/UploadFiles/FCKeditor/20210905114336.pdfIn PDF document text
    • http://futimisdev.com/userfiles/file/pevarapodifoza.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_off0000d675.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD675 17540 bytes
SHA-256: e940ab73f9edba1158b21a72ce289468b1387148d265ac41b5004e952b1b50b7
font_01_sfnt_off000103c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103C4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011bdb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11BDB 10736 bytes
SHA-256: a597011fa12c06dc4f03730d513c4f8108f529bb84a4336a6fe8019fd4ef73b8