Malicious PDF — malware analysis report

Static analysis result for SHA-256 a99436308b33b1f7…

MALICIOUS

PDF

81.9 KB Created: 2021-08-28 14:35:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 9bad2713dba71b562c04d178a66697c5 SHA-1: e4d6295ae1490485fd783cc6a06e14e4c80dfd5d SHA-256: a99436308b33b1f7f0d74ef51938db43177df2d1afd0e7e4a8799205c5e7fa4b
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains a large number of links, many pointing to disposable hosting or compromised CMS upload directories, suggesting a link farm designed to distribute malicious content or phish users. The document body is unreadable binary data, indicating it's not intended for direct user consumption but rather as a container for these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9917

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 http://saptpadi.com/files/file/buzenumepinuwodalowik.pdf In PDF document text
    • http://dzstock.com/Upfiles/file/zutobojisok.pdfIn PDF document text
    • http://bogelaipigeon.com/upload/file/xololemobuzewilapesajuf.pdfIn PDF document text
    • http://sad-azov.ru/wp-content/plugins/super-forms/uploads/php/files/e79a26fd7708a06f725362ba78a55a4c/38372794843.pdfIn PDF document text
    • https://pfgmm.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160842fa9973b0---kapomuwilomisa.pdfIn PDF document text
    • http://fittbike.hu/files/file/44856801498.pdfIn PDF document text
    • http://accurateverdicts.com/wp-content/plugins/formcraft/file-upload/server/content/files/160896453a90bc---96439049478.pdfIn PDF document text
    • https://mmszke.hu/files/file/91242222522.pdfIn PDF document text
    • https://www.newhorizonscrisiscenter.org/ckfinder/userfiles/files/36949458629.pdfIn PDF document text
    • https://shotclock.ca/wp-content/plugins/super-forms/uploads/php/files/bd54a40c87090dfecf0d42c440fc3895/78376081381.pdfIn PDF document text
    • https://faprosid.com/file/logapidixirevijamejuji.pdfIn PDF document text
    • https://www.jahnigterbraak.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1608baac27b99e---wurexedubiru.pdfIn PDF document text
    • http://media-production.net/admin/ckfinder/userfiles/files/sofupukajizofalil.pdfIn PDF document text
    • https://www.cir.cloud/wp-content/plugins/formcraft/file-upload/server/content/files/160856853d7be0---38102723054.pdfIn PDF document text
    • http://www.uppld.org/wp-content/plugins/formcraft/file-upload/server/content/files/160852353e796b---wekuzojiwu.pdfIn PDF document text
    • https://ak-oroslavje.hr/files/tulubem.pdfIn PDF document text
    • https://www.vibrationmonitoring.asia/wp-content/plugins/formcraft/file-upload/server/content/files/160c4482253305---rujud.pdfIn PDF document text
    • http://apsons.eu/files/file/49733987704.pdfIn PDF document text
    • http://staceyasp.com/UserFiles/file/44750902488.pdfIn PDF document text
    • https://izharfoster.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609ac988567dd---wusesijotozixudefara.pdfIn PDF document text
    • http://skup-laptopow.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607df5ce4d2a5---gaxinunawibufenunisit.pdfIn PDF document text
    • http://erisalaw-chicago.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/zomosejimotuwirurexu.pdfIn PDF document text
    • http://www.infranetltd.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607548784d62c---nesali.pdfIn PDF document text
    • https://toyotaautobody.com/ckfinder/userfiles/files/polepinefolosipukitazo.pdfIn PDF document text
    • https://jxloanchien.com/style/postimage/file/66368318172.pdfIn PDF document text
    • http://www.belladermeestetica.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160f54bec799c2---tasesopugekogazebilesox.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/zMnd8XtcwSM/uplcv?utm_term=mmr2+vaccine+meaningPDF link annotation
    • 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_off0000dc39.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC39 10320 bytes
SHA-256: 7be96cb0a84ac99992af0730547215799d06e3c9f7d8f63513f232bae380fcca
font_01_sfnt_off0000f38b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF38B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010b9d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B9D 17864 bytes
SHA-256: 251e1f979e34e9d7b99374045d7c5ce4a217f7eb0aae43c120eeba238371b618