Malicious PDF — malware analysis report

Static analysis result for SHA-256 91f3c81ce961042d…

MALICIOUS

PDF

86.1 KB Created: 2021-07-01 15:17:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 0a817c1604422682320620874b71860a SHA-1: 2a8f2eb954cc9f338c31b52c64c3b0838eb3e295 SHA-256: 91f3c81ce961042dec62bbe85e1cc1561983cdbc172be5f31126aa92d7ef191c
156 Risk Score

Malware Insights

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

The PDF file contains a large number of embedded URLs, many of which point to compromised WordPress upload directories. The ML classifier and ClamAV both strongly indicate maliciousness, with ClamAV identifying it as Pdf.Phishing.Trojan. The primary attack pattern appears to be a link farm designed to direct users to potentially malicious content, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

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://www.potterycommercials.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16079d084c1340---14969133517.pdf
    • http://treeoflifetolfu.com/clients/0/07/07f122ebb3396bb3f917f2e62af81596/File/xuvalabijonekidatejutub.pdf
    • https://estidevelopers.com/wp-content/plugins/super-forms/uploads/php/files/b2767db9cedac74095a3dff2ea1c023f/61686660473.pdf
    • https://alice-immo.com/userfiles/file/58459994333.pdf
    • https://inclinedigital.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607406939669f---xenorixajapizam.pdf
    • https://hoffmanowska.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160893a788fc37---95605885617.pdf
    • http://riggi.ru/userfiles/file/tebopanavozatapu.pdf
    • http://sinara.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/16073c049e163c---vatam.pdf
    • http://www.pianoszimmermann.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16077bca51eb9e---5812735199.pdf
    • https://laihouston.com/wp-content/plugins/super-forms/uploads/php/files/3512abf3a8ff334b1c80911a8ba7b656/50011349757.pdf
    • https://morethancleaningservices.com/wp-content/plugins/super-forms/uploads/php/files/0468145ee6c8f8617ae03d40bd1adc52/musem.pdf
    • http://www.next-conseil.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160c5eeec4ba02---vamozonakogelimuroz.pdf
    • https://relleno-acidohialuronico.com/wp-content/plugins/super-forms/uploads/php/files/81f661a83472d0be8f993870f5319a79/49706641581.pdf
    • http://shannonlakeestates.org/fck_images/file/80447548165.pdf
    • http://dmn.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1609aade1d27f7---46583467193.pdf
    • https://law.com.sg/wp-content/plugins/super-forms/uploads/php/files/c80e8230cc8a4f23154e6a35c7cef917/83717126125.pdf
    • http://ndt-tl.ru/upload/file/tebobudixetemabavar.pdf
    • https://caribemed.com/userfiles/file/49624347012.pdf
    • https://home18.ru/wp-content/plugins/super-forms/uploads/php/files/3187b1370a3228e877b67f3efc284f27/xubekolasowug.pdf
    • http://www.orarestauratorisaf.it/wp-content/plugins/formcraft/file-upload/server/content/files/160704c7f4d5d6---mojunaludedokul.pdf
    • http://acecaalcoy.com/userfiles/file/suzofulisuzifafepupog.pdf
    • https://skazkavdom.com/wp-content/plugins/super-forms/uploads/php/files/c1036d7e9ac86d962c47a0c94576ac1b/69684746884.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/PmAiG5ZyT-k/uplcv?utm_term=how+to+get+free+textbook
    • 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_off0000f090.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF090 16792 bytes
font_01_sfnt_off000108a2.bin
0470be6d8599b9d8a21f7078f70b1fab248fcf02db985edb91cfc611a3e46149
pdf-font-stream PDF embedded font (sfnt) at offset 0x108A2 16856 bytes
font_02_sfnt_off0001347c.bin
d7a14ed15445832b360e23532f3f216091d4782efadeae30203060fe9b53684f
pdf-font-stream PDF embedded font (sfnt) at offset 0x1347C 10228 bytes