Malicious PDF — malware analysis report

Static analysis result for SHA-256 815cbae272fe9b05…

MALICIOUS

PDF

78.6 KB Created: 2021-04-08 10:56:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 7cc7206453d52e7494b4b136e7251218 SHA-1: 5ba3663fc9f73c5f8fa3fe2869c8616fc111a21e SHA-256: 815cbae272fe9b05a877ad906d649693695f21605bfb19ad51d5bf15b0e67ce5
186 Risk Score

Malware Insights

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

The PDF file contains a large number of external links, identified as a link farm. Several heuristics indicate this is a SEO link farm on disposable hosting, with one URL pointing to zajinet.ru. The ClamAV detection and ML classifier strongly suggest malicious intent, likely related to phishing or malware distribution through the linked content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

Heuristics 6

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://zajinet.ru/strik?utm_term=2x4+outdoor+furniture+plans+free
    • https://vupixesit.weebly.com/uploads/1/3/2/7/132740805/2194764.pdf
    • https://cdn-cms.f-static.net/uploads/4473044/normal_601090b569af1.pdf
    • https://lonexababite.weebly.com/uploads/1/3/1/1/131163854/84edc3.pdf
    • http://alifan.store/fusajazesarujotebx2.pdf
    • https://zuveravovizopow.weebly.com/uploads/1/3/0/9/130969477/1327025.pdf
    • http://remontnatali.ru/free_autocad_floor_plan_dwgnnmb8.pdf
    • https://cdn-cms.f-static.net/uploads/4388420/normal_6019504f7ef2e.pdf
    • https://static.s123-cdn-static.com/uploads/4369330/normal_5ff17165304e8.pdf
    • http://masito.space/guitar_chords_guide_for_beginnersaa09f.pdf
    • https://fanamavikere.weebly.com/uploads/1/3/4/6/134610997/xabivamiwotos.pdf
    • https://zurowesijeja.weebly.com/uploads/1/3/4/6/134630916/fapuxodararuju_dutufesevo_ropedulafufabix.pdf
    • https://tupivoxutod.weebly.com/uploads/1/3/4/4/134467409/subumimujufim_difenovakorig_rezesep_mojozatibovaj.pdf
    • http://hhizmet.com/jane_austen_pride_and_prejudice_short_summaryr008q.pdf
    • https://dojilosadokadog.weebly.com/uploads/1/3/4/8/134890500/davofifugilo.pdf
    • https://tixosame.weebly.com/uploads/1/3/4/5/134523113/mubanewol-gezutipajifagus-jadajigakaj-sewitexenipiz.pdf
    • https://fuwemuwiwogul.weebly.com/uploads/1/3/4/0/134016804/7972490.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://321e46d8-a3e9-4523-905f-b0dcd1dcb7ef.filesusr.com/ugd/29fbc3_3919bcdfa32f4974bd50d4379338b64a.pdf?index=true
    • https://uploads.strikinglycdn.com/files/e9959830-5a47-4b13-bf35-ab430ea5cbd3/stihl_ts420_carburetor_fuel_line_diagram.pdf
    • https://uploads.strikinglycdn.com/files/caad43b1-a682-44ba-99df-303ca8a6890e/11027798010.pdf
    • https://0eb00d84-361a-45dc-b346-1af5c8eb785c.filesusr.com/ugd/d79848_152945e0892a4f3da7d4a4acb8304fa6.pdf?index=true
    • https://uploads.strikinglycdn.com/files/d7f4d29b-aada-4c43-ab3e-cb34615fd29c/chicago_manual_of_style_16th_edition_example.pdf
    • https://ed4d48c2-14ea-47f5-a89a-b82193587323.filesusr.com/ugd/8ce377_b670de56e28641c6a75b6bc8ad38e55d.pdf?index=true
    • https://uploads.strikinglycdn.com/files/23762557-d2f7-4644-8aa3-e903c3eb7758/ge_microwave_troubleshooting_f3_code.pdf
    • https://ca3ec1ac-6ff7-4c8f-ae0f-86a30d86e335.filesusr.com/ugd/3615fb_06adaa43db6a47089e40e91c3899c20e.pdf?index=true
    • https://d2497fa9-5496-4194-9764-f4b168485e88.filesusr.com/ugd/eed259_c7b90de8e79b433c8792911f83c48b45.pdf?index=true
    • 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://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f5d0.bin
57d7a3883105557f70f67c13c4bff8e67d9b907380477e719680d6253af3356c
pdf-font-stream PDF embedded font (sfnt) at offset 0xF5D0 5228 bytes
font_01_sfnt_off000107b3.bin
f8df89802449f2b2e968d5d7bc36d9bffee2e7df8237b468d00d561773529c9e
pdf-font-stream PDF embedded font (sfnt) at offset 0x107B3 11000 bytes