Malicious PDF — malware analysis report

Static analysis result for SHA-256 a1f4b5a26b642a38…

MALICIOUS

PDF

70.9 KB Created: 2021-09-26 04:24:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 6b2199c1dcd70c96847081d0f404c7cb SHA-1: 7a65adbba22d9cb5327b9adf2c5826237dab75bb SHA-256: a1f4b5a26b642a3867056cb41c38376782ed4006f26269545d3d8133a08aaa27
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. Heuristics reveal it functions as a link farm, with numerous embedded URLs pointing to compromised WordPress sites and other domains, likely serving as a distribution point for phishing or malware. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user consumption but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

Heuristics 6

  • 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.
  • 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://medvor.ru/uplcv?utm_term=among+lock+apk PDF link annotation
    • http://cohn-vossen.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614d9c9b5d9c6---4642155366.pdfIn PDF document text
    • https://xn--i1aam8cb.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/eaaa720fd40dfc9fb23502a348676f68/waravufaninevom.pdfIn PDF document text
    • https://www.le-domaine-de-hauterive.fr/ckfinder/userfiles/files/puwamigovob.pdfIn PDF document text
    • http://inewbus.com/wp-content/plugins/super-forms/uploads/php/files/o2pc1bnahkdt99dp2vj332dr92/jobutozisoduwenomipi.pdfIn PDF document text
    • http://www.holderit.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613fd550eb352---kalatewejimarozukugugup.pdfIn PDF document text
    • http://myucpb.com/userfiles/file/sunekawojutufu.pdfIn PDF document text
    • http://lyzph.com/userfiles/file/Fl202109260652517497.pdfIn PDF document text
    • http://autoscuolapezzano.it/userfiles/files/75560084142.pdfIn PDF document text
    • http://condominiobrisasdelnorte.com/userfiles/file/pemawedibosanelanuta.pdfIn PDF document text
    • https://gaseg.com/wp-content/plugins/super-forms/uploads/php/files/5bgpeqatkv1kgjol9hjqmitkbm/28395651111.pdfIn PDF document text
    • http://creativecoms.net/userfiles/file/retitototoza.pdfIn PDF document text
    • http://startent.ru/SITE/files/editor/file/xotirezisozujapixufuwekim.pdfIn PDF document text
    • http://travelshops.pl/userfiles/file/mejofel.pdfIn PDF document text
    • http://mixline.ru/img/lib/file/zugufaponigeliw.pdfIn PDF document text
    • http://studiotecnicopetrillo.eu/userfiles/files/20929975845.pdfIn PDF document text
    • https://www.die-umzugsfabrik.com/wp-content/plugins/formcraft/file-upload/server/content/files/161365de74dd08---wefubozegapokepuw.pdfIn PDF document text
    • http://erbaytag.com/resimler/files/bufogupixizenuzumetagakez.pdfIn PDF document text
    • http://rapet.hu/files/92966722874.pdfIn PDF document text
    • https://olterus.net/contents/files/60597843550.pdfIn PDF document text
    • http://www.aamuhsv-madisonalumni.org/files/files/54592303687.pdfIn PDF document text
    • http://alwaysshine.com/fileimage/file/96227496402.pdfIn PDF document text
    • https://akonis.ch/userfiles/files/nobumo.pdfIn PDF document text
    • http://chiangmai-clean.com/user_img/files/xajibasule.pdfIn PDF document text
    • https://vresponse.net/userfiles/file/domamikaxurit.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_off0000b1f3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB1F3 18184 bytes
SHA-256: 4fb636f7423bd7ecfbd9dea8ac571b7fe263cdd8ffbd886518c45a094cca179b
font_01_sfnt_off0000dfd2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFD2 10200 bytes
SHA-256: 8827a9939ca5140e9f74ad093ae4df6a89b862e45704b4dd60970045990e10e0
font_02_sfnt_off0000f6af.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6AF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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