Malicious PDF — malware analysis report

Static analysis result for SHA-256 a99b2a3e037c5638…

MALICIOUS

PDF

86.3 KB Created: 2021-07-24 07:46:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 665031f22ec263f387f7ffa6c776e318 SHA-1: 16cfcae3fd33ab8201c3b6361d0d05e96015e86f SHA-256: a99b2a3e037c5638aebabc234a96cf385b8d06981fd7df19c3955d2707d08ad1
156 Risk Score

Malware Insights

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

The sample is a PDF file detected as malicious by ClamAV and an ML classifier. It functions as a link farm, containing numerous URLs pointing to compromised WordPress sites and other domains, likely to distribute further malware or conduct phishing. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a pattern of using disposable hosting for link farms, suggesting an attempt to manipulate search engine results or redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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 http://korvet-sp.ru/userfiles/file/65791908061.pdf In PDF document text
    • https://markeishahall.com/wp-content/plugins/super-forms/uploads/php/files/8335ec9ea7eb5c7f0286f9d0f9a1eeb1/1291992422.pdfIn PDF document text
    • https://namastehealth.in/wp-content/plugins/super-forms/uploads/php/files/suk43inan7661hp6pev85pjaub/57363390437.pdfIn PDF document text
    • http://oikoscoccatoarchitettura.com/userfiles/files/gifebimugasi.pdfIn PDF document text
    • https://mission4recruitment.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f647f57675e---tajap.pdfIn PDF document text
    • https://www.coconutlodge.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a56c0e6b90c---93772708758.pdfIn PDF document text
    • http://norilskgu.ru/userfiles/file/xiparikewigeribozek.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ae7b32d67c6---wudelesatuwon.pdfIn PDF document text
    • https://kp-bs.ru/upload/files/78753798407.pdfIn PDF document text
    • http://www.oknookna.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1606d8dcd366f0---wuxanorute.pdfIn PDF document text
    • https://dcmheavyequipment.com/admin/images/file/zevoli.pdfIn PDF document text
    • http://karunb.com/UpLoads/files/74588819088.pdfIn PDF document text
    • https://journeypeople.cc/wp-content/plugins/super-forms/uploads/php/files/68966d00ea461ca08371be12db8c4d3b/dupukovarid.pdfIn PDF document text
    • https://globalazeri.az/wp-content/plugins/super-forms/uploads/php/files/cp955kt2dsfameg9108khq15d5/gidugakazoxamimano.pdfIn PDF document text
    • https://www.apollopowersystems.com/wp-content/plugins/super-forms/uploads/php/files/43c5e54c24feb442090a6ad5a77dc06e/51279182873.pdfIn PDF document text
    • http://koreaseals.com/ckfinder/userfiles/files/wenasivarisadetunomagizu.pdfIn PDF document text
    • http://hncastlecable.com/d/files/boxejulola.pdfIn PDF document text
    • https://micast.de/wp-content/plugins/super-forms/uploads/php/files/iqevfjf7jui5s3ub6foselj2st/zemazuvewijovutotikumobep.pdfIn PDF document text
    • https://sport-jicin.cz/dokumenty/boxobudej.pdfIn PDF document text
    • https://daleplumbinginc.com/wp-content/plugins/super-forms/uploads/php/files/e3e0ab746db1aa5f57add3dd9a6bbe1a/bezigav.pdfIn PDF document text
    • http://stratford1980.com/clients/1/19/19838be1bbe5684469623718d5e25b5d/File/95729054380.pdfIn PDF document text
    • https://cristiandellavedova.com/wp-content/plugins/super-forms/uploads/php/files/6utpgv33c6r8qffdf0qcrflqp5/19638968222.pdfIn PDF document text
    • http://jeugdopdewetenschapsagenda.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160aaabce623c3---83067607536.pdfIn PDF document text
    • http://www.zopfitravel.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c59fea78f70---ferufujedimuruso.pdfIn PDF document text
    • http://milcontabil.com.br/wp-content/plugins/super-forms/uploads/php/files/pecdtnp1sgldv53h3fmgbadne3/sajoruk.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=pronoms+personnels+exercices+en+lignePDF 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_off0000ea3b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA3B 18940 bytes
SHA-256: 908185f02cceed0f724ec5e3a56bf414579208b62c720f985af73c2ef70663be
font_01_sfnt_off000119d0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x119D0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000131e7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x131E7 10560 bytes
SHA-256: a8db0039caa780e07f42a12b4c9a42789406a812ac297b6e1c3c86431dd07b47

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