Malicious PDF — malware analysis report

Static analysis result for SHA-256 8d9386eed731fa57…

MALICIOUS

PDF

90.9 KB Created: 2021-07-12 22:54:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 329eb030fd38b2afa6dfdfd64820edd4 SHA-1: fd41969fb8d15c86b18c8b24e71224f62a7845cd SHA-256: 8d9386eed731fa57b0688ad7613f897d083c48fb8bd552f69990fbef5bc48ada
164 Risk Score

Malware Insights

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

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and by an ML classifier, indicating malicious intent. It contains numerous embedded URLs, many pointing to compromised WordPress sites, and a specific URL with a 'reply email for interview invitation' UTM term, suggesting a phishing lure. The presence of a 'download button' heuristic further supports the attack pattern of tricking users into downloading a payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

Heuristics 7

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://krisoc.ru/uplcv?utm_term=reply+email+for+interview+invitation
    • http://skup-laptopow.com/wp-content/plugins/formcraft/file-upload/server/content/files/160718c011b675---76971191394.pdf
    • http://henca.com/files/details/file/xemabemexutogugewidape.pdf
    • http://slowjamsundays.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bd0a642df74---2984200846.pdf
    • https://www.tangelo.no/wp-content/plugins/formcraft/file-upload/server/content/files/160710fb254233---jotiluwivumewug.pdf
    • http://phenix-security.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1607f70696abcf---11641232305.pdf
    • http://oletrans.sk/editor_uploads/files/wixodamutawekizutuxiwoli.pdf
    • http://cedresarquitectura.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b6622dd8188---65632990980.pdf
    • http://xn--d1achljw0b.xn--p1ai/content/upload/93421814937.pdf
    • https://gbeequestriansurfaces.com/wp-content/plugins/super-forms/uploads/php/files/rnhdm05qiq2dge0kkel8kcqo8q/rivet.pdf
    • http://weddingdiy.cc/uploadfiles/files/20210606_012035_6899.pdf
    • http://berbun.com/user_img/file/95316394450.pdf
    • http://csc0311.com/userfiles/file/20210624053248_a98608.pdf
    • http://www.timtransportes.com/home/wp-content/plugins/formcraft/file-upload/server/content/files/1606eac2fdc38f---48320905107.pdf
    • http://ucinnovation.ru/admin/ckfinder/userfiles/files/61077574662.pdf
    • http://aiskreunion.com/clients/b/b4/b417c2091670ce0b0d78f4b231aea02c/File/4922066592.pdf
    • http://www.wallisandemmanuel.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c3109b6f05a---jabuwatizile.pdf
    • https://xn--8--clcp3bi.xn--p1ai/files/47457356379.pdf
    • https://www.physioaktivkramer.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607e2bc80a56b---wowazigawajirovotat.pdf
    • https://malashealthcare.com/userfiles/files/zevasajumisipanofat.pdf
    • http://onishi-kyosendo.jp/archive/gexakonupo.pdf
    • https://akproauto.com/nbloom/fckuploads/file/71047747809.pdf
    • http://johndanton.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/sanazevifizex.pdf
    • https://wpsqld.com.au/wp-content/plugins/super-forms/uploads/php/files/3774eee5e1d3c7dddf83ac70dd6acbf2/43857760315.pdf
    • https://robertmatzuzi-massagetherapist.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16071f5fe41b83---sebamatij.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00010249.bin
cf47df1e2c286044859cfd0ea983f136072277c5bf3084aa38a970fabcd14092
pdf-font-stream PDF embedded font (sfnt) at offset 0x10249 10660 bytes
font_01_sfnt_off00011ab7.bin
721fe8ce8fd4c9cdc21d33ba70dca38b089847275a219d0eea9a0a6b7c2e362d
pdf-font-stream PDF embedded font (sfnt) at offset 0x11AB7 16828 bytes
font_02_sfnt_off0001466a.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1466A 16792 bytes